Chin. J. Org. Chem. ›› 2017, Vol. 37 ›› Issue (5): 1189-1197.DOI: 10.6023/cjoc201703024 Previous Articles     Next Articles



高燕娇, 肖振华, 刘良先, 黄培强   

  1. 福建省化学生物学重点实验室 能源材料化学协同创新中心 厦门大学化学化工学院化学系 厦门 361005
  • 收稿日期:2017-03-13 修回日期:2017-04-01 发布日期:2017-04-10
  • 通讯作者: 刘良先,黄培强;
  • 基金资助:


Direct Reductive Cyanation of A 2-Pyrrolidinone Chiral Building Block Bearing An Unprotected Hydroxyl Group: A Stereoselective Synthesis of N-Methyl-2-epi-bulgecinine

Gao Yanjiao, Xiao Zhenhua, Liu Liangxian, Huang Peiqiang   

  1. Fujian Provincial Key Laboratory of Chemical Biology, Collaborative Innovation Centre of Chemistry for Energy Materials, Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005
  • Received:2017-03-13 Revised:2017-04-01 Published:2017-04-10
  • Contact: 10.6023/cjoc201703024;
  • Supported by:

    Project supported by the National Natural Science Foundation of China (No. 21332007) and the Program for Changjiang Scholars and Innovative Research Team in University of Ministry of Education.

The direct reductive cyanation of N-benzyl-4-benzyloxy-5-hydroxymethyl-2-pyrrolidinone (3a), a lactam bearing a free hydroxyl group, has been achieved with the LiAlH4/KCN combination. The reaction afforded 2,5-trans-2-cyano-5-hydroxylmethyl-4-benzyloxy-pyrrolidine (5a) and its cis-diastereomer 5b in a ratio of 69:31 with a combined yield of 63%. The observed 2,5-trans-stereoselectivity is suggested to be resulted from both stereoelectronic effect and allylic 1,3-strain between the hydroxymethyl group at C(5) and the incoming cyanide anion on the presumed Δ-1 pyrrolinium ion intermediate. The subsequent hydrolysis of the cyano group of the diastereomeric mixture 5a/5b (trans:cis=69:31) under basic conditions afforded the corresponding 5-hydroxymethyl-4-benzyloxyproline with 2,5-cis-diastereomer as the major diastereomer (trans:cis=10:90). This result implies that a synthetically useful epimerization at C(2) has occurred concomitantly. This unexpected result afforded a concise and highly stereoselective synthesis of 2,5-cis-(-)-N-methyl-2-epi-bulgecinine.

Key words: amides, nitriles, iminium ion, stereoselective synthesis, epimerization