化学学报 ›› 2017, Vol. 75 ›› Issue (12): 1196-1201.DOI: 10.6023/A17080372 上一篇    下一篇

研究通讯

钯配合物和手性磷酸连续催化的烯丙醇和醛的不对称羰基烯丙基化反应

张子競a, 陶忠林a, 阿拉法特·阿地力a, 龚流柱a,b   

  1. a 中国科学技术大学 化学与材料科学学院 合肥 230026;
    b 合肥微尺度物质科学国家实验室(筹) 合肥 230026
  • 收稿日期:2017-08-14 出版日期:2017-12-15 发布日期:2017-10-09
  • 通讯作者: 龚流柱,E-mail:gonglz@ustc.edu.cn E-mail:gonglz@ustc.edu.cn
  • 基金资助:

    项目受国家自然科学基金(No.21232007)资助.

Asymmetric Carbonyl Allylation of Aldehydes with Allylic Alcohols under the Sequential Catalysis of Palladium Complex and Chiral Phosphoric Acid

Zhang Zi-Jinga, Tao Zhong-Lina, Arafate Adelea, Gong Liu-Zhua,b   

  1. a School of Chemistry and Materials Science, University of Science and Technology of China, Hefei 230026;
    b Hefei National Laboratory for Physical Sciences at Microscale, Hefei 230036
  • Received:2017-08-14 Online:2017-12-15 Published:2017-10-09
  • Contact: 10.6023/A17080372 E-mail:gonglz@ustc.edu.cn
  • Supported by:

    Project supported by the National Natural Science Foundation of China (No. 21232007).

利用钯配合物/手性磷酸催化剂体系,通过不对称连续催化,实现了烯丙醇和醛的不对称羰基烯丙基化反应.该反应使用廉价易得的烯丙醇底物,在催化量的手性磷酸作用下,以优秀的产率和立体选择性得到了高烯丙醇产物.

关键词: 不对称催化, 钯催化, 手性磷酸, 羰基烯丙基化, 烯丙醇

The asymmetric carbonyl allylation of aldehydes with allylmetal reagents presents one of the most efficient and straightforward methods for the synthesis of optically active homoallylic alcohols, which have found widespread applications in organic synthesis. As such, a wide range of chiral catalysts, including Lewis acids, Lewis bases and Brønsted acids have been reported to enable highly stereoselective carbonyl allylation of aldehydes with allylmetal reagents. Among them, chiral phosphoric acid-catalyzed carbonyl allylation of aldehydes with pinacol allylboronates represents a promising method, whereas an additional operations required for the preparation of allylboronates from allyl halides or highly active allylmetallics impose some constraints on the carbonyl allylation process. In this context, the asymmetric addition of allylboronates, in situ generated from palladium-catalyzed allylborylation, to aldehydes has been reported, while stoichiometric amounts of chiral diboronate reagents are basically required. Allylic alcohols are readily available feedstock. The direct use of allylic alcohols as starting materials in asymmetric allylborylation of carbonyls is highly valuable. Herein, we will report an asymmetric carbonyl allylation of aldehydes with allylic alcohols in the presence of octamethyl-2,2'-bi(1,3,2-dioxaborolane) under the sequential catalysis of a palladium complex and chiral phosphoric acid. The presence of 2.5 mol% (η3-C3H5)2Pd2Cl2, 5 mol% P(OPh)3 and 10 mol% chiral phosphoric acid B*H-1 enabled 4-nitrobenzaldehyde 2a to smoothly undergo the asymmetric carbonyl allylation reaction with 2-buten-1-ol 1a and octamethyl-2,2'-bi(1,3,2-dioxaborolane), giving rise to the desired homoallylic alcohol product 3aa in a 99% yield and with >20:1 dr and 92% ee. Under the optimal conditions, the generality for allylic alcohol substrates was investigated to reveal that the installation of either of saturated alkyl substituents, carbon-carbon double bond or heteroatom group in the allylic alcohols allowed the target products (3ca~3fa, 3ha~3ja) to be obtained in high yields and with excellent stereoselectivities. A (Z)-allylic alcohol and branched allylic alcohols were also able to generate the target products (3ba, 3ga), successfully. Although cinnamic alcohols participated in a clean reaction, relatively lower yields and stereoselectivity were delivered (3ka and 3la). The examination of aldehydes suggested that the introduction of either electronically deficient or rich substituents to the benzene ring of benzaldehydes was tolerant and led to corresponding homoallylic alcohols in excellent yields and stereoselectivities (3ab~3ak and 3m), with the exception of o-anisaldehyde (3al). In addition, 2-naphthaldehyde, aliphatic aldehydes and enals are all good substrates and provide high yields and enantiomeric excesses as exemplified by 3-phenylpropanal and 4-methoxycinnamaldehyde (3an~3ap).

Key words: asymmetric catalysis, palladium catalysis, chiral phosphoric acid, carbonyl allylation, allylic alcohol