Acta Chim. Sinica ›› 2016, Vol. 74 ›› Issue (12): 984-989.DOI: 10.6023/A16100541 Previous Articles     Next Articles

Special Issue: 聚集诱导发光



叶旭a, 曾兴平a, 周剑a,b   

  1. a 华东师范大学化学与分子工程学院 绿色化学与化工过程绿色化上海市重点实验室 上海 200062;
    b 中国科学院上海有机化学研究所 金属有机化学国家重点实验室 上海 200032
  • 投稿日期:2016-10-12 发布日期:2016-12-20
  • 通讯作者: 曾兴平, 周剑;
  • 基金资助:


A Comparison of Me2(CH2Cl)SiCN and Me3SiCN in Catalytic Enantioselective Cyanation of Aldehydes

Ye Xua, Zeng Xingpinga, Zhou Jiana,b   

  1. a Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai 200062;
    b State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, CAS, Shanghai 200032, China
  • Received:2016-10-12 Published:2016-12-20
  • Supported by:

    Project supported by the National Natural Science Foundation of China (No. 21472049).

We report the comparative studies of Me2(CH2Cl) SiCN and Me3SiCN in the catalytic enantioselective cyanation reactions of aldehydes,which were catalyzed by the merger of 5 mol% Jacobsen's catalyst (salen) AlCl (R,R)-1 and 6 mol% ylide 2a,and are conducted at -50℃ using i-Pr2O as the solvent.This was based on our recent finding that (R,R)-1 could be effectively activated by ylide to form an enhanced chiral Lewis acid.Generally,the use of Me2(CH2Cl) SiCN as the cyanating reagent afforded obviously higher activity in the reaction of all the aldehydes we examined,along with by-and-large similar enantioselectivity.This further suggested that Me2(CH2Cl) SiCN might be useful cyanating reagent to develop reaction involving the use of less active substrates.Under the indicated condition,aromatic aldehydes worked well to give the desired adducts in up to 99% yield and 94% ee,but the reactions of vinyl aldehydes and aliphatic aldehydes were not successful.All the reactions were performed by the following general procedure.To a 4 mL vial were successively added complex (R,R)-1(30.3 mg,0.05 mmol),ylide 2a (22.6 mg,0.06 mmol) and i-Pr2O (1.0 mL).The resulting solution was stirred at -50℃ for 0.5 h before the addition of aldehydes (1.0 mmol) and the cyanating reagent,Me2(CH2Cl) SiCN or Me3SiCN (250 μL,2.0 mmol).After TLC analysis indicated the full consumption of the aldehydes,the reaction mixture was filtrated with a pad of silica gel and eluted with Et2O.The filtrate is concentrated under reduced pressure to give a crude residue for column chromatography purification.In contrast,when Me2(CH2Cl) SiCN is used,both cyanohydrins and its silyl ethers were obtained,so a further deprotection by p-TsOH is adopted to obtain free cyanohydrins as the only product.

Key words: enantioselective cyanation, TMSCN, Me2(CH2Cl) SiCN, (Salen) AlCl/ylide complex, chiral cyanohydrins