ARTICLES

Regio-reversed [3+2] Cycloaddition of Triketone Enones with Nitrones

  • Tianjiao Han b ,
  • Qianqian Shi , a, * ,
  • Yundong Fu , a, * ,
  • Guangjian Mei , b, *
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  • a State Key Laboratory of Antiviral Drugs, Pingyuan Laboratory, Henan Normal University, Xinxiang, Henan 453007
  • b College of Chemistry and Pingyuan Laboratory, Zhengzhou University, Zhengzhou 450001

Received date: 2025-07-15

  Revised date: 2025-08-26

  Online published: 2025-09-18

Supported by

National Natural Science Foundation of China(22371265)

National Natural Science Foundation of China(22403027)

Natural Science Foundation of Henan Province(232301420047)

Natural Science Foundation of Henan Province(222300420084)

Abstract

Triketone alkenes represent a class of highly electron-deficient unsaturated carbonyl compounds and serve as important and versatile synthetic building blocks. In previous work, triketone enones usually undergo β-selective conjugate addition or cycloaddition. It is challenging to achieve regio-reversed conjugate addition or cycloaddition of triketone enones. Based on previous work, regio-reversed [3+2] cycloaddition of triketone enones with nitrones was achieved, and a series of isoxazolidines were synthesized effectively and stereoselectively under catalyst-free conditions, with up to 95% yield and 20∶1 dr. It exhibits green properties, easy operation and a wide substrate range, offering a reference for isoxazolidine synthesis. Density functional theory (DFT) study reveals that this regio-reversed [3+2] cycloaddition is energetically favorable.

Cite this article

Tianjiao Han , Qianqian Shi , Yundong Fu , Guangjian Mei . Regio-reversed [3+2] Cycloaddition of Triketone Enones with Nitrones[J]. Chinese Journal of Organic Chemistry, 2026 , 46(1) : 146 -155 . DOI: 10.6023/cjoc202507022

烯酮是一种重要的有机结构单元, 也是许多天然产物和药物分子的合成砌块[1-4]. 在烯酮参与的方法学研究中, 1,4-共轭加成或环加成是常见的反应类型[5-8]. 由于电子效应的存在, 烯酮通常发生β-选择性的1,4-共轭加成或β-选择性的环加成, 而反常区域选择性(即α-选择性)的1,4-共轭加成或环加成反应被认为更具挑战 性[9-11]. 烯酮和1,3-偶极体通常发生β-选择性的[3+2]环加成, 而α-选择性的[3+2]环加成研究报道较少(Scheme 1, a).
图式1 三酮烯烃与硝酮区域选择性反常的[3+2]环加成反应

Scheme 1 Regio-reversed [3+2] cycloaddition of triketone enones with nitrones

三酮烯烃是一类特殊的烯酮底物和重要的合成砌块, 在α-位有两个酮羰基, 在β-位有一个酮羰基, 也是一种高度缺电子的不饱和羰基化合物. 由于三酮烯烃的α-位具有空间位阻, 而且β-位具有电性优势, 两种效应共同导致三酮烯烃参与的β-选择性共轭加成或环加成反应最为常见. 吴安心等[12-16]报道了三酮烯烃与亲核试剂的β-加成-环化反应, 合成了呋喃衍生物和其它杂环. 卢一新和丁奎岭等[17]报道了一种手性膦(NUSIOC- Phos)催化的三酮烯烃与烯丙酸酯的β-选择性串联反应, 制备了双环缩醛类化合物. 我们课题组报道了布朗斯特酸催化三酮烯烃与2-吲哚甲醇的氧杂迈克尔加成-串联反应, 得到了四环吲哚类化合物.
三酮烯烃与1,3-偶极体通常发生β-选择性的[3+2]环加成反应(Scheme 1, b). 而实现三酮烯烃反常区域选择性(即α-选择)的共轭加成或环加成具有挑战性, 关键在于克服电子效应和空间效应. 2024年, 我们课题组[18]报道了首例三酮烯烃反常区域选择性的不对称串联环化反应, 合成了双环呋喃衍生物. 基于课题组前期的研究基础, 我们设想发展更多三酮烯烃反常区域选择性的方法学. 硝酮是一种重要的有机合成中间体, 也是一种常见的1,3-偶极子, 其与缺电子烯烃类化合物的[3+2]环加成反应取得了一定的研究进展, 但区域选择性和立体选择性的控制仍然是一个难题[19-25]. 在此, 我们将报道三酮烯烃与硝酮区域选择性反常的[3+2]环加成反应, 在无催化剂的条件下高效和高立体选择性地合成一系列异噁唑五元杂环(Scheme 1, c), 该类异噁唑五元杂环是一类特殊的氮氧杂环, 存在于众多天然产物和药物分子结构中, 具有潜在的生物活性[26-27].

1 结果与讨论

1.1 反应条件的优化

以三酮烯烃(1a)和硝酮(2a)为原料, 探索三酮烯烃与硝酮区域选择性反常的[3+2]环加成反应的最佳条 件, 结果见表1. 首先, 探索了不同类型的溶剂对反应的影响(Entries 1~4). 结果显示, 在室温下只有以甲苯作溶剂时该反应才能够发生, 以大于20∶1的非对映选择性和25%的收率得到反常区域选择性的产物3a, 且没有检测到正常区域选择性产物4a. 然后, 探索了不同反应温度对反应收率的影响(Entries 5~7). 当反应温度从室温提升到80 ℃, 收率随着温度的升高而增加. 但当温度升至80 ℃时, 收率并没有继续增加, 说明该反应的最佳反应温度为80 ℃. 最后, 考察了反应时间对反应收率的影响, 当反应时间延长到24 h时(Entries 8~9), 反应收率有微弱的提高, 达到91%. 综上所述, 该消旋反应的最佳反应条件为: 以1 mL甲苯作溶剂, 三酮烯烃(1a, 0.2 mmol)和硝酮(2a, 0.2 mmol)在80 ℃反应24 h. 我们还尝试了催化不对称反应条件的筛选, 有机小分子催化剂的引入并没有实现对产物对映选择性的控制.
表1 反应条件优化a

Table 1 Optimization of reaction condition

Entry Solvent Time/h Temp./℃ Yieldb/% of 3a/4a drc of 3a
1 Toluene 12 r.t. 25/0 >20∶1
2 CH3CN 12 r.t. N.D.
3 DCM 12 r.t. N.D.
4 THF 12 r.t. N.D.
5 Toluene 12 60 72/0 >20∶1
6 Toluene 12 70 88/0 >20∶1
7 Toluene 12 80 88/0 >20∶1
8 Toluene 18 80 90/0 >20∶1
9 Toluene 24 80 91/0 >20∶1

a Reaction conditions: 1a (0.2 mmol), 2a (0.2 mmol.), solvent (1 mL). b Isolated yields. c Determined by 1H NMR. N.D.=Not detected.

1.2 反应底物拓展

在最优的反应条件下, 考察了该条件的适用范围(Schemes 2, 3). 首先, 考察了不同的三酮烯烃1与硝酮2a的反应(3a~3o). 结果显示三酮烯烃1中苯基上不同给电子取代基(例如甲基、甲氧基)或吸电子取代基(例如硝基、氟、氯、溴)对反应均具有较好的适用性, 且苯环上取代基的位置对反应收率影响不大, 均能保持优异的收率. 将三酮烯烃1中的苯基替换为萘基, 该反应仍具有较好的适用性.
图式2 三酮烯烃底物拓展

Scheme 2 Substrate scopes of triketone enones

图式3 硝酮底物拓展

Scheme 3 Substrate scopes of nitrones

接下来使用三酮烯烃1a和硝酮2进行反应(3p~3ac). 结果显示当R为甲基且Ar'为苯基或取代苯基时, 在苯基上引入不同的给电子基团(甲基和甲氧基)或不同的吸电子取代基(如卤素)后, 该反应同样具有良好的适用性. 此外, 当将Ar'由苯基替换为萘环、呋喃或噻吩杂环时, 反应收率基本能够保持. 另外, 当将R由甲基替换为苄基时, 该反应仍能保持良好的收率.

1.3 立体构型的确认

为了确定产物的立体构型, 选择固体形态较好的产物(±)-3i进行了单晶的培养, 使用二氯甲烷/正己烷(体积比为1∶1)作溶剂, 利用液相扩散法得到单晶. 通过X射线单晶衍射实验确定了产物(±)-3i是反式构型(图1), 其它产物的立体构型通过类比可以得到.
图1 化合物(±)-3i的单晶

Figure 1 X-ray single crystal diffraction of (±)-3i

1.4 理论计算和反应机理研究

为了解释这种反常区域选择性, 进行了DFT理论计算并分析了反应的关键过渡态. 如图2所示, 经过渡态TS1, 1a2a发生反常区域选择性的[3+2]环加成反应(ΔG=62.3 kJ/mol), 形成C(1)—C键和C(2)—O键, 并生成了实际监测到的产物3a. 对于可能的竞争性产物或中间体也进行了计算. 2a的氧负离子经过渡态TS1'G=71.1 kJ/mol)亲核进攻三酮烯烃的C(1), 生成中间体INT1. 此外, 1a2a发生正常区域选择性的[3+2]环加成反应, 经过渡态TS1''G=77.4 kJ/mol), 形成C(1)—O键和C(2)—C键, 并得到竞争性产物a. DFT计算结果表明, 与过渡态TS1相关的路径在能量上最有利. 计算结果与实验得到的结果相符合. 另外, 还计算了反应物1a中C(1)和C(2)原子的局部亲电指数, C(1)和C(2)原子的亲电指数(Pk)分别为0.125和0.211, 与过渡态TS1G=62.3 kJ/mol)和TS1'G=71.1 kJ/mol)之间的能垒差异一致.
图2 不同路径的相对吉布斯自由能计算

Figure 2 Relative Gibbs free energy profiles for the different pathways

2 结论

报道了三酮烯烃与硝酮反常区域选择性的[3+2]环加成反应, 高效、高立体选择性地合成出29例异噁唑烷五元杂环. 该方法无需催化剂, 具有绿色环保、操作简便及底物适用范围广的优点, 为异噁唑烷类化合物的合成提供了参考. 同时进行了DFT理论计算以解释这种反常区域选择性, 不同路径的计算结果显示, 这种反常的区域选择性环加成反应在能量上是有利的.

3 实验部分

3.1 仪器与试剂

核磁共振谱(1H NMR、13C NMR、19F NMR)使用BRUKER 400 MHz核磁共振仪(TMS为内标)测定, CDCl3为溶剂; 高分辨质谱使用Q-TOF Micro LC/MS System ESI质谱仪测定. 所有溶剂和试剂均为市售分析纯. 反应均采用薄层色谱法(TLC)进行监测, 薄层色谱使用的预涂硅胶板来源于青岛海洋化工有限公司. 产物均利用柱层析进行纯化, 以石油醚和乙酸乙酯为洗脱剂, 硅胶使用240~400目. 三酮烯烃底物和硝酮底物的合成参考文献[28-29].

3.2 实验方法

3.2.1 异噁唑烷3的合成

将三酮烯烃1 (0.2 mmol)、硝酮2 (mmol)和甲苯(1 mL)加入密封管中, 在80 ℃下搅拌24 h, 使用薄层色谱法检测反应. 反应完成后, 直接减压浓缩除去溶剂, 所得粗产物用柱层析纯化(石油醚/乙酸乙酯, VV=10∶1~6∶1), 得到目标产物3.
1,1'-(4-苯甲酰-2-甲基-3-苯基异噁唑烷-5,5-二基)双(乙-1-酮)(3a): 白色固体, 产率91%. m.p. 98.2~99.1 ℃; 1H NMR (400 MHz, CDCl3) δ: 7.77 (d, J=7.5 Hz, 2H), 7.48 (t, J=7.4 Hz, 1H), 7.31 (t, J=7.8 Hz, 2H), 7.29~7.25 (m, 3H), 7.22~7.15 (m, 2H), 5.51 (d, J=8.3 Hz, 1H), 3.96 (d, J=8.3 Hz, 1H), 2.71 (s, 3H), 2.36 (d, J=2.4 Hz, 6H); 13C NMR (100 MHz, CDCl3) δ: 204.2, 202.9, 198.2, 136.4, 136.2, 133.8, 129.2, 128.9, 128.7, 128.5, 128.2, 97.5, 78.4, 63.8, 42.7, 28.3, 24.7; HRMS (ESI) calcd for C21H21NO4Na [M+Na] 374.1363, found 374.1367.
1,1'-(4-(4-氟苯甲酰)-2-甲基-3-苯基异噁唑烷-5,5-二基)双(乙-1-酮)(3b): 白色固体, 产率85%. m.p. 152.7~ 153.4 ℃; 1H NMR (400 MHz, CDCl3) δ: 7.88~7.73 (m, 2H), 7.32~7.27 (m, 3H), 7.23~7.13 (m, 2H), 6.98 (t, J=8.6 Hz, 2H), 5.44 (d, J=8.4 Hz, 1H), 3.98 (d, J=8.4 Hz, 1H), 2.71 (s, 3H), 2.36 (d, J=3.4 Hz, 6H); 13C NMR (100 MHz, CDCl3) δ: 204.1, 203.0, 196.5, 166.2 (d, J=256.6 Hz), 136.1, 132.9 (d, J=2.8 Hz), 132.0 (d, J=9.7 Hz), 129.0, 128.8, 128.1, 115.7 (d, J=22.0 Hz), 97.4, 78.3, 63.8, 42.7, 28.3; 19F NMR (376 MHz, CDCl3) δ: -103.5; HRMS (ESI) calcd for C21H20FNO4Na [M+Na] 392.1268, found 392.1276.
1,1'-(4-(4-氯苯甲酰)-2-甲基-3-苯基异噁唑烷-5,5-二基)双(乙-1-酮)(3c): 白色固体, 产率87%. m.p. 135.8~ 136.2 ℃; 1H NMR (400 MHz, CDCl3) δ: 7.72 (d, J=8.6 Hz, 2H), 7.34~7.26 (m, 5H), 7.22~7.14 (m, 2H), 5.42 (d, J=8.4 Hz, 1H), 3.97 (d, J=8.4 Hz, 1H), 2.71 (s, 3H), 2.35 (d, J=3.2 Hz, 6H); 13C NMR (100 MHz, CDCl3) δ: 204.0, 202.9, 197.0, 140.5, 136.0, 134.8, 130.6, 129.0, 128.9, 128.8, 128.1, 97.5, 78.3, 63.8, 42.7, 28.3, 24.7; HRMS (ESI) calcd for C21H20ClNO4Na [M+Na] 408.0973, found 408.0977.
1,1'-(4-(4-溴苯甲酰)-2-甲基-3-苯基异噁唑烷-5,5-二基)双(乙-1-酮)(3d): 白色固体, 产率82%. m.p. 147.8~148.3 ℃; 1H NMR (400 MHz, CDCl3) δ: 7.64 (d, J=8.6 Hz, 2H), 7.46 (d, J=8.6 Hz, 2H), 7.35~7.26 (m, 3H), 7.22~7.14 (m, 2H), 5.41 (d, J=8.4 Hz, 1H), 3.97 (d, J=8.4 Hz, 1H), 2.71 (s, 3H), 2.35 (d, J=3.1 Hz, 6H); 13C NMR (100 MHz, CDCl3) δ: 204.0, 202.9, 197.3, 136.0, 135.2, 131.8, 130.6, 129.4, 129.0, 128.9, 128.1, 97.5, 78.3, 63.8, 42.7, 28.3, 24.7; HRMS (ESI) calcd for C21H21Br- NO4Na [M+Na] 452.0468, found 452.0473.
1,1'-(2-甲基-4-(4-硝基苯甲酰)-3-苯基异噁唑烷-5,5-二基)双(乙-1-酮)(3e): 白色固体, 产率89%. m.p. 110.6~111.3 ℃; 1H NMR (400 MHz, CDCl3) δ: 8.17 (d, J=8.5 Hz, 2H), 7.97 (d, J=8.4 Hz, 2H), 7.37~7.27 (m, 3H), 7.24~7.13 (m, 2H), 5.44 (d, J=8.5 Hz, 1H), 4.01 (d, J=8.4 Hz, 1H), 2.73 (s, 3H), 2.38 (s, 6H); 13C NMR (100 MHz, CDCl3) δ: 203.8, 203.0, 197.4, 150.5, 141.0, 135.6, 130.1, 129.1, 129.1, 127.9, 123.6, 97.7, 78.4, 64.2, 42.7, 28.4, 24.8; HRMS (ESI) calcd for C21H20N2O6Na [M+ Na] 419.1213, found 419.1217.
1,1'-(4-(2-氯苯甲酰)-2-甲基-3-苯基异噁唑烷-5,5-二基)双(乙-1-酮)(3f): 白色固体, 产率76%. m.p. 142.9~143.4 ℃; 1H NMR (400 MHz, CDCl3) δ: 7.54 (d, J=7.6 Hz, 1H), 7.31~7.27 (m, 2H), 7.25~7.18 (m, 4H), 7.16~7.10 (m, 2H), 5.33 (d, J=8.5 Hz, 1H), 3.90 (d, J=8.5 Hz, 1H), 2.70 (s, 3H), 2.45 (s, 3H), 2.35 (s, 3H); 13C NMR (100 MHz, CDCl3) δ: 203.8, 202.9, 199.8, 137.4, 135.9, 132.5, 131.6, 130.7, 130.5, 128.8, 128.7, 127.8, 126.7, 97.5, 78.9, 67.4, 42.6, 28.5, 24.7; HRMS (ESI) calcd for C21H20ClNO4Na [M+Na] 408.0973, found 408.0981.
1,1'-(4-(3-溴苯甲酰)-2-甲基-3-苯基异噁唑烷-5,5-二基)双(乙-1-酮)(3g): 白色固体, 产率79%. m.p. 125.3~126.1 ℃; 1H NMR (400 MHz, CDCl3) δ: 7.87 (d, J=1.6 Hz, 1H), 7.69 (d, J=7.9 Hz, 1H), 7.60 (dd, J=8.0, 0.9 Hz, 1H), 7.36~7.27 (m, 3H), 7.25~7.12 (m, 3H), 5.41 (d, J=8.4 Hz, 1H), 3.92 (d, J=8.4 Hz, 1H), 2.71 (s, 3H), 2.37 (d, J=6.2 Hz, 6H); 13C NMR (100 MHz, CDCl3) δ: 203.9, 202.8, 197.0, 138.1, 136.6, 135.9, 132.0, 130.1, 129.0, 128.9, 128.1, 127.9, 122.8, 97.5, 78.4, 64.0, 42.7, 28.3, 24.7; HRMS (ESI) calcd for C21H21BrNO4Na [M+Na] 452.0468, found 452.0472.
1,1'-(4-(2-氟苯甲酰)-2-甲基-3-苯基异噁唑烷-5,5-二基)双(乙-1-酮)(3h): 白色固体, 产率78%. m.p. 153.2~154.1 ℃; 1H NMR (400 MHz, CDCl3) δ: 7.68~7.58 (m, 1H), 7.48~7.36 (m, 1H), 7.30~7.22 (m, 3H), 7.20~7.07 (m, 3H), 6.99~6.89 (m, 1H), 5.45 (d, J=8.3 Hz, 1H), 3.87 (d, J=8.3 Hz, 1H), 2.69 (s, 3H), 2.40 (s, 3H), 2.35 (s, 3H); 13C NMR (100 MHz, CDCl3) δ: 203.6, 202.8, 197.4 (d, J=2.8 Hz), 161.1 (d, J=258.8 Hz), 135.0 (d, J=9.2 Hz), 131.0, 131.0, 128.8, 128.7, 128.0, 126.1 (d, J=10.2 Hz), 124.2 (d, J=3.7 Hz), 116.7 (d, J=22.7 Hz), 97.8, 78.9, 66.8, 66.8, 42.6, 28.4, 24.7; 19F NMR (376 MHz, CDCl3) δ: -111.0; HRMS (ESI) calcd for C21H20FNO4Na [M+Na] 392.1268, found 392.1274.
1,1'-(2-甲基-4-(4-甲基苯甲酰)-3-苯基异噁唑烷-5,5-二基)双(乙-1-酮)(3i): 白色固体, 产率91%. m.p. 151.2~152.1 ℃; 1H NMR (400 MHz, CDCl3) δ: 7.67 (d, J=8.2 Hz, 2H), 7.32~7.23 (m, 4H), 7.2~7.16 (m, 2H), 7.11 (d, J=8.1 Hz, 2H), 5.47 (d, J=8.3 Hz, 1H), 3.97 (d, J=8.3 Hz, 1H), 2.71 (s, 3H), 2.34 (s, 6H), 2.33 (s, 3H); 13C NMR (100 MHz, CDCl3) δ: 204.2, 202.9, 197.5, 144.9, 136.3, 133.9, 129.3, 129.2, 128.9, 128.7, 128.2, 97.5, 78.3, 63.7, 42.7, 28.2, 24.7, 21.6; HRMS (ESI) calcd for C22H24NO4Na [M+Na] 388.1519, found 388.1523.
1,1'-(2-甲基-4-(3-甲基苯甲酰)-3-苯基异噁唑烷-5,5-二基)双(乙-1-酮)(3j): 白色固体, 产率83%. m.p. 111.8~112.3 ℃; 1H NMR (400 MHz, CDCl3) δ: 7.56 (d, J=7.7 Hz, 1H), 7.47 (s, 1H), 7.33~7.26 (m, 4H), 7.23~7.13 (m, 3H), 5.49 (d, J=8.3 Hz, 1H), 3.88 (d, J=8.3 Hz, 1H), 2.70 (s, 3H), 2.36 (d, J=5.9 Hz, 6H), 2.23 (s, 3H); 13C NMR (100 MHz, CDCl3) δ: 204.2, 202.7, 198.2, 138.2, 136.3, 136.2, 134.6, 129.8, 128.9, 128.7, 128.4, 128.3, 126.5, 97.5, 78.5, 64.2, 42.7, 28.3, 24.7, 21.1; HRMS (ESI) calcd for C22H23NO4Na [M+Na] 388.1519, found 388.1529.
1,1'-(2-甲基-4-(2-甲基苯甲酰)-3-苯基异噁唑烷-5,5-二基)双(乙-1-酮)(3k): 白色固体, 产率83%. m.p. 145.6~147.3 ℃; 1H NMR (400 MHz, CDCl3) δ: 7.46 (d, J=7.8 Hz, 1H), 7.31~7.22 (m, 4H), 7.19~7.10 (m, 3H), 7.07 (t, J=7.6 Hz, 1H), 5.37 (d, J=8.4 Hz, 1H), 3.87 (d, J=8.4 Hz, 1H), 2.70 (s, 3H), 2.42 (d, J=3.2 Hz, 6H), 2.35 (s, 3H); 13C NMR (100 MHz, CDCl3) δ: 204.0, 203.2, 201.5, 139.1, 136.9, 136.1, 132.1, 131.7, 130.3, 128.9, 128.7, 128.0, 125.7, 97.7, 79.3, 66.5, 42.7, 28.5, 24.8, 21.4; HRMS (ESI) calcd for C22H24NO4Na [M+Na] 388.1519, found 388.1522.
1,1'-(4-(2-甲氧基苯甲酰)-2-甲基-3-苯基异噁唑烷- 5,5-二基)双(乙-1-酮)(3l): 白色固体, 产率82%. m.p. 128.1~129.0 ℃; 1H NMR (400 MHz, CDCl3) δ: 7.55~7.46 (m, 1H), 7.43~7.32 (m, 1H), 7.26~7.20 (m, 3H), 7.13~7.02 (m, 2H), 6.92 (t, J=7.5 Hz, 1H), 6.67 (d, J=8.4 Hz, 1H), 5.74 (d, J=7.9 Hz, 1H), 3.69 (d, J=7.9 Hz, 1H), 3.23 (s, 3H), 2.65 (s, 3H), 2.35 (d, J=15.6 Hz, 6H); 13C NMR (100 MHz, CDCl3) δ: 204.4, 202.3, 201.1, 158.4, 137.5, 134.2, 130.8, 128.4, 128.3, 128.2, 127.7, 120.4, 111.3, 98.2, 79.0, 67.5, 54.6, 42.5, 28.2, 24.5; HRMS (ESI) calcd for C22H23NO5Na [M+Na] 404.1468, found 404.1479.
1,1'-(4-(3-甲氧基苯甲酰)-2-甲基-3-苯基异噁唑烷- 5,5-二基)双(乙-1-酮)(3m): 白色固体, 产率81%. m.p. 153.6~154.2 ℃; 1H NMR (400 MHz, CDCl3) δ: 7.34 (d, J=7.7 Hz, 1H), 7.32~7.26 (m, 4H), 7.24~7.17 (m, 3H), 7.07~6.99 (m, 1H), 5.48 (d, J=8.3 Hz, 1H), 3.92 (d, J=8.3 Hz, 1H), 3.68 (s, 3H), 2.71 (s, 3H), 2.36 (d, J=4.5 Hz, 6H); 13C NMR (100 MHz, CDCl3) δ: 204.3, 202.7, 197.8, 159.5, 137.5, 136.3, 129.5, 128.9, 128.8, 128.2, 122.0, 121.2, 112.5, 97.5, 78.4, 64.2, 55.2, 42.7, 28.3, 24.7. HRMS (ESI) calcd for C22H23NO5Na [M+Na] 404.1468, found 404.1472.
1,1'-(4-(4-甲氧基苯甲酰)-2-甲基-3-苯基异噁唑烷- 5,5-二基)双(乙-1-酮)(3n): 白色固体, 产率92%. m.p. 152.6~153.1 ℃; 1H NMR (400 MHz, CDCl3) δ: 7.76 (d, J=8.9 Hz, 2H), 7.32~7.25 (m, 3H), 7.22~7.15 (m, 2H), 6.86~6.69 (m, 2H), 5.44 (d, J=8.3 Hz, 1H), 3.99 (d, J=8.3 Hz, 1H), 3.79 (s, 3H), 2.71 (s, 3H), 2.34 (s, 6H); 13C NMR (100 MHz, CDCl3) δ: 204.4, 203.0, 196.0, 164.1, 136.4, 131.7, 129.4, 128.9, 128.7, 128.2, 113.7, 97.4, 78.2, 63.6, 55.4, 42.7, 28.2, 24.7; HRMS (ESI) calcd for C22H23NO5Na [M+Na] 404.1468, found 404.1475.
1,1'-(4-(2-萘甲酰基)-2-甲基-3-苯基异噁唑烷-5,5-二基)双(乙-1-酮)(3o): 白色固体, 产率81%. m.p. 150.2~151.1 ℃; 1H NMR (400 MHz, CDCl3) δ: 8.10 (s, 1H), 7.93~7.84 (m, 1H), 7.77 (t, J=7.5 Hz, 2H), 7.65 (d, J=8.1 Hz, 1H), 7.58~7.50 (m, 1H), 7.50~7.40 (m, 1H), 7.32~7.26 (m, 3H), 7.24~7.18 (m, 2H), 5.67 (d, J=8.3 Hz, 1H), 3.94 (d, J=8.2 Hz, 1H), 2.73 (s, 3H), 2.39 (d, J=7.3 Hz, 6H); 13C NMR (100 MHz, CDCl3) δ: 204.4, 202.7, 197.7, 136.4, 135.8, 133.4, 132.3, 132.1, 130.0, 129.0, 128.9, 128.8, 128.3, 127.6, 126.7, 124.0, 97.6, 64.4, 42.8, 28.3, 24.7; HRMS (ESI) calcd for C25H23NO4Na [M+ Na] 424.1519, found 424.1526.
1,1'-(4-苯甲酰-3-(4-氟苯基)-2-甲基异噁唑烷-5,5-二基)双(乙-1-酮)(3p): 白色固体, 产率91%. m.p. 153.6~154.2 ℃; 1H NMR (400 MHz, CDCl3) δ: 7.77 (d, J=7.5 Hz, 2H), 7.50 (t, J=7.4 Hz, 1H), 7.34 (t, J=7.8 Hz, 2H), 7.23~7.08 (m, 2H), 6.97 (t, J=8.6 Hz, 2H), 5.46 (d, J=8.3 Hz, 1H), 3.96 (d, J=8.3 Hz, 1H), 2.70 (s, 3H), 2.35 (d, J=3.4 Hz, 6H); 19F NMR (376 MHz, CDCl3) δ: -112.75; 13C NMR (100 MHz, CDCl3) δ: 204.0, 202.8, 198.0, 162.8 (d, J=247.8 Hz), 136.3, 134.0, 132.1 (d, J=3.2 Hz) 129.9 (d, J=8.2 Hz), 129.1, 128.5, 115.9 (d, J=21.6 Hz), 97.4, 63.6, 42.6, 28.3, 24.7; HRMS (ESI) calcd for C21H21F- NO4Na [M+Na] 392.1268, found 392.1273.
1,1'-(4-苯甲酰-3-(4-氯苯基)-2-甲基异噁唑烷-5,5-二基)双(乙-1-酮)(3q): 白色固体, 产率79%. m.p. 152.6~153.1 ℃; 1H NMR (400 MHz, CDCl3) δ: 7.84~7.74 (m, 2H), 7.51 (t, J=7.4 Hz, 1H), 7.35 (t, J=7.8 Hz, 2H), 7.28~7.21 (m, 2H), 7.17~7.09 (m, 2H), 5.45 (d, J=8.3 Hz, 1H), 3.98 (d, J=8.3 Hz, 1H), 2.70 (s, 3H), 2.34 (d, J=1.7 Hz, 6H); 13C NMR (100 MHz, CDCl3) δ: 203.9, 202.7, 197.9, 136.3, 134.9, 134.6, 134.0, 129.5, 129.1, 129.1, 128.6, 97.4, 63.5, 42.7, 28.3, 24.72; HRMS (ESI) calcd for C21H20ClNO4Na [M+Na] 408.0973, found 408.0976.
1,1'-(4-苯甲酰-3-(4-溴苯基)-2-甲基异噁唑烷-5,5-二基)双(乙-1-酮)(3r): 白色固体, 产率73%. m.p. 112.6~113.2 ℃; 1H NMR (400 MHz, CDCl3) δ: 7.87~7.71 (m, 2H), 7.57~7.47 (m, 1H), 7.45~7.39 (m, 2H), 7.38~7.30 (m, 2H), 7.12~7.00 (m, 2H), 5.45 (d, J=8.3 Hz, 1H), 3.97 (d, J=8.3 Hz, 1H), 2.70 (s, 3H), 2.34 (d, J=1.2 Hz, 6H); 13C NMR (100 MHz, CDCl3) δ: 203.9, 202.7, 197.9, 136.3, 135.4, 134.0, 132.1, 129.8, 129.2, 128.6, 122.8, 97.4, 77.5, 63.5, 42.7, 28.3, 24.7; HRMS (ESI) calcd for C21H20BrNO4Na [M+Na] 452.0468, found 452.0475.
1,1'-(4-苯甲酰-3-(2-氯苯基)-2-甲基异噁唑烷-5,5-二基)双(乙-1-酮)(3s): 白色固体, 产率72%. m.p. 152.6~153.1 ℃; 1H NMR (400 MHz, CDCl3) δ: 7.82~7.71 (m, 2H), 7.53~7.46 (m, 1H), 7.47~7.41 (m, 1H), 7.37~7.26 (m, 3H), 7.25~7.16 (m, 2H), 5.45 (d, J=7.9 Hz, 1H), 4.61 (d, J=7.9 Hz, 1H), 2.76 (s, 3H), 2.37 (d, J=14.2 Hz, 6H); 13C NMR (100 MHz, CDCl3) δ: 203.9, 202.6, 198.0, 136.6, 134.4, 134.3, 133.8, 129.6, 129.5, 129.0, 129.0, 128.5, 127.7, 97.9, 73.2, 63.1, 42.7, 28.4, 24.6; HRMS (ESI) calcd for C21H20ClNO4Na [M+Na] 408.0973, found 408.0978.
1,1'-(4-苯甲酰-3-(3-氯苯基)-2-甲基异噁唑烷-5,5-二基)双(乙-1-酮)(3t): 白色固体, 产率73%. m.p. 115.6~116.3 ℃; 1H NMR (400 MHz, CDCl3) δ: 7.89~7.72 (m, 2H), 7.52 (t, J=7.4 Hz, 1H), 7.36 (t, J=7.8 Hz, 2H), 7.28~7.16 (m, 3H), 7.08 (d, J=7.4 Hz, 1H), 5.45 (d, J=8.3 Hz, 1H), 4.01 (d, J=8.3 Hz, 1H), 2.72 (s, 3H), 2.34 (d, J=4.4 Hz, 6H); 13C NMR (100 MHz, CDCl3) δ: 203.8, 202.7, 197.8, 138.4, 136.3, 134.7, 134.0, 130.2, 129.2, 129.0, 128.6, 128.1, 126.3, 97.4, 77.4, 63.4, 42.8, 28.3, 24.7; HRMS (ESI) calcd for C21H20ClNO4Na [M+Na] 408.0973, found 408.0977.
1,1'-(4-苯甲酰-2-甲基-3-(对甲苯基)异噁唑烷-5,5-二基)双(乙-1-酮)(3u): 白色固体, 产率74%. m.p. 152.6~153.1 ℃; 1H NMR (400 MHz, CDCl3) δ: 7.78 (d, J=7.4 Hz, 2H), 7.48 (t, J=7.4 Hz, 1H), 7.32 (t, J=7.8 Hz, 2H), 7.07 (s, 4H), 5.48 (d, J=8.3 Hz, 1H), 3.92 (d, J=8.3 Hz, 1H), 2.70 (s, 3H), 2.35 (d, J=3.0 Hz, 6H), 2.30 (s, 3H); 13C NMR (100 MHz, CDCl3) δ: 204.2, 202.9, 198.3, 138.6, 136.4, 133.8, 133.1, 129.6, 129.2, 128.5, 128.1, 97.5, 78.2, 63.8, 42.6, 28.3, 24.7, 21.1; HRMS (ESI) m/z calcd for C22H23NO4Na [M+Na]388.1519, found 388.1526.
1,1'-(4-苯甲酰-2-甲基-3-(邻甲苯基)异噁唑烷-5,5-二基)双(乙-1-酮)(3v): 白色固体, 产率77%. m.p. 115.6~116.3 ℃; 1H NMR (400 MHz, CDCl3) δ: 7.76 (d, J=7.6 Hz, 2H), 7.48 (t, J=7.4 Hz, 1H), 7.41~7.27 (m, 3H), 7.21 (t, J=7.5 Hz, 1H), 7.14 (t, J=7.4 Hz, 1H), 7.00 (d, J=7.5 Hz, 1H), 5.48 (d, J=8.3 Hz, 1H), 4.33 (d, J=8.3 Hz, 1H), 2.70 (s, 3H), 2.36 (d, J=4.0 Hz, 6H), 2.05 (s, 3H); 13C NMR (100 Hz, CDCl3) δ: 204.3, 202.8, 198.4, 136.8, 136.4, 134.4, 133.9, 130.4, 129.0, 128.5, 128.1, 127.7, 126.9, 97.7, 64.0, 42.6, 28.3, 24.7, 19.4; HRMS (ESI) calcd for C22H23NO4Na [M+Na] 388.1519, found 388.1528.
1,1'-(4-苯甲酰-2-甲基-3-(间甲苯基)异噁唑烷-5,5-二基)双(乙-1-酮)(3w): 白色固体, 产率95%. m.p. 145.6~146.3 ℃; 1H NMR (400 MHz, CDCl3) δ: 7.78 (d, J=7.6 Hz, 2H), 7.47 (t, J=7.4 Hz, 1H), 7.31 (t, J=7.7 Hz, 2H), 7.16 (t, J=7.6 Hz, 1H), 7.11~7.04 (m, 1H), 7.01~6.93 (m, 2H), 5.49 (d, J=8.4 Hz, 1H), 3.95 (d, J=8.3 Hz, 1H), 2.71 (s, 3H), 2.35 (s, 6H), 2.27 (s, 3H); 13C NMR (100 MHz, CDCl3) δ: 204.1, 202.9, 198.2, 138.6, 136.5, 136.1, 133.8, 129.5, 129.2, 128.8, 128.7, 128.4, 125.2, 97.5, 78.4, 63.8, 42.8, 28.3, 24.8, 21.3; HRMS (ESI) calcd for C22H23NO4Na [M+Na] 388.1519, found 388.1523.
1,1'-(4-苯甲酰-3-(4-甲氧基苯基)-2-甲基异噁唑烷- 5,5-二基)双(乙-1-酮)(3x): 白色固体, 产率93%. m.p. 152.6~153.1 ℃; 1H NMR (400 MHz, CDCl3) δ: 7.82~ 7.70 (m, 2H), 7.53~7.44 (m, 1H), 7.32 (t, J=7.8 Hz, 2H), 7.16~7.06 (m, 2H), 6.86~6.75 (m, 2H), 5.48 (d, J=8.3 Hz, 1H), 3.90 (s, 1H), 3.76 (s, 3H), 2.69 (s, 3H), 2.35 (d, J=6.5 Hz, 6H); 13C NMR (100 MHz, CDCl3) δ: 204.2, 202.9, 198.3, 159.9, 136.4, 133.8, 129.4, 129.2, 128.5, 128.0, 114.2, 97.5, 78.0, 63.7, 55.2, 42.6, 28.3, 24.7; HRMS (ESI) calcd for C22H23NO5Na [M+Na] 404.1468, found 404.1471.
1,1'-(4-苯甲酰-3-(3-甲氧基苯基)-2-甲基异噁唑烷- 5,5-二基)双(乙-1-酮)(3y): 白色固体, 产率87%. m.p. 132.6~133.3 ℃; 1H NMR (400 MHz, CDCl3) δ: 7.78 (d, J=7.4 Hz, 2H), 7.49 (t, J=6.5 Hz, 1H), 7.38~7.25 (m, 2H), 7.22~7.14 (m, 1H), 6.85~6.79 (m, 1H), 6.78~6.70 (m, 2H), 5.56~5.41 (m, 1H), 3.94 (d, J=7.9 Hz, 1H), 3.79~3.68 (m, 3H), 2.79~2.65 (m, 3H), 2.44~2.28 (m, 6H); 13C NMR (100 MHz, CDCl3) δ: 204.0, 202.9, 198.2, 159.9, 137.8, 136.4, 133.8, 129.9, 129.2, 128.5, 120.4, 114.3, 113.3, 97.5, 78.2, 63.7, 55.2, 42.8, 28.3, 24.7; HRMS (ESI) calcd for C22H23NO5Na [M+Na] 404.1468, found 404.1473.
1,1'-(4-苯甲酰-2-甲基-3-(萘-2-基)异噁唑烷-5,5-二基)双(乙-1-酮)(3z): 白色固体, 产率81%. m.p. 137.2~138.0 ℃; 1H NMR (400 MHz, CDCl3) δ: 7.83~7.76 (m, 4H), 7.75~7.70 (m, 1H), 7.60 (s, 1H), 7.51~7.40 (m, 3H), 7.39~7.33 (m, 1H), 7.30~7.22 (m, 2H), 5.62 (d, J=8.3 Hz, 1H), 4.17 (d, J=8.3 Hz, 1H), 2.74 (s, 3H), 2.39 (d, J=1.7 Hz, 6H); 13C NMR (100 MHz, CDCl3) δ: 204.2, 202.9, 198.2, 136.4, 133.9, 133.6, 133.4, 133.1, 129.21, 129.0, 128.5, 128.0, 127.9, 127.7, 126.4, 126.4, 125.0, 97.6, 78.6, 63.5, 42.8, 28.4, 24.8; HRMS (ESI) calcd for C25H23NO4Na [M+Na] 424.1519, found 424.1526.
1,1'-(4-苯甲酰-2-甲基-3-(噻吩-2-基)异噁唑烷-5,5-二基)双(乙-1-酮)(3aa): 白色固体, 产率63%. m.p. 100.3~101.1 ℃; 1H NMR (400 MHz, CDCl3) δ: 7.85 (d, J=7.6 Hz, 2H), 7.53 (t, J=7.4 Hz, 1H), 7.37 (t, J=7.8 Hz, 2H), 7.28 (s, 1H), 6.95 - 6.81 (m, 2H), 5.50 (d, J=8.0 Hz, 1H), 4.32 (d, J=8.0 Hz, 1H), 2.79 (s, 3H), 2.33 (s, 6H); 13C NMR (100 MHz, CDCl3) δ: 203.4, 202.5, 197.8, 138.9, 136.4, 134.0, 129.2, 128.6, 127.1, 126.8, 126.6, 97.4, 73.3, 64.0, 42.8, 28.2, 24.6; HRMS (ESI) calcd for C19H19NO4SNa [M+Na] 380.0927, found 380.0933.
1,1'-(4-苯甲酰-3-(呋喃-2-基)-2-甲基异噁唑烷-5,5-二基)双(乙-1-酮)(3ab): 白色固体, 产率77%. m.p. 135.6~136.3 ℃; 1H NMR (400 MHz, CDCl3) δ: 7.90 (d, J=7.6 Hz, 2H), 7.54 (t, J=7.4 Hz, 1H), 7.40 (t, J=7.8 Hz, 3H), 6.30~6.25 (m, 2H), 5.73 (d, J=8.3 Hz, 1H), 4.10 (d, J=8.4 Hz, 1H), 2.81 (s, 3H), 2.32 (d, J=11.6 Hz, 6H); 13C NMR (100 MHz, CDCl3) δ: 203.4, 197.7, 148.1, 143.5, 136.3, 134.0, 129.2, 128.6, 110.5, 110.2, 97.5, 70.9, 59.7, 43.1, 28.2, 24.6; HRMS (ESI) calcd for C19H19N- O5Na [M+Na] 364.1155, found 364.1162.
1,1'-(4-苯甲酰-2-苄基-3-苯基异噁唑烷-5,5-二基)双(乙-1-酮)(3ac): 白色固体, 产率94%. m.p. 134.7~135.3 ℃; 1H NMR (400 MHz, DMSO-d6) δ: 7.66 (d, J=7.3 Hz, 2H), 7.60 (t, J=7.4 Hz, 1H), 7.41 (t, J=7.8 Hz, 2H), 7.38~7.30 (m, 7H), 7.28~7.23 (m, 2H), 5.37 (d, J=8.3 Hz, 1H), 4.20 (d, J=8.3 Hz, 1H), 3.87 (q, J=14.5 Hz, 2H), 2.30 (s, 3H), 1.98 (s, 3H); 13C NMR (100 MHz, DMSO-d6) δ: 204.2, 203.0, 198.4, 137.0, 136.7, 136.6, 134.6, 129.5, 129.9, 129.3, 129.2, 128.9, 128.6, 128.3, 127.9, 97.5, 76.0, 63.3, 59.0, 28.77, 24.9; HRMS (ESI) calcd for C27H26NO4Na [M+Na] 450.1676, found 450.1684.

3.2.2 理论计算方法与细节

所有理论计算均在郑州大学使用Gaussian 09软件包进行, 采用密度泛函理论(DFT)方法. 几何构型优化使用了M06-2X泛函[30]以及6-31G(d,p)基组[31]. 此外, 在M06-2X/6-311++G(2df,2pd)[32]水平上进行单点能量计算, 采用积分方程形式极化连续介质模型(IEF- PCM)[33], 溶剂为甲苯. 此外, 优化后的过渡态的三维结构通过使用CYL View进行可视化[34].
辅助材料(Supporting Information) 目标化合物3a~3ac的核磁共振图谱、理论计算细节和单晶数据. 这些材料可以免费从本刊网站(http://sioc-journal.cn/)上下载.
(Zhao, C.)
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