Organocatalysis in Synthesis: L-Proline as an Enantioselective Catalyst in the Synthesis of Pyrans and Thiopyrans

Molecules

Noha M. Hilmy Elnagdi¹ 

关键词: L-proline;    pyran;    assymetric synthesis;    enantioselectivity;    ethyl propiolate;    optical activity;   

DOI  :  10.3390/molecules17044300

来源: mdpi

【 摘 要 】

The multicomponent reaction (MCR) of aromatic aldehydes 1 and malononitrile (2) with active methylenes 5a–h in the presence of L-proline produced pyrans and thiopyrans 6a–h stereospecifically and in good yields. Moreover a novel MCR of ethyl propiolate (8) with 1 and 2 in the presence of L-proline to afford (R)-polysubstituted pyran is also reported. X-ray structures, e.e. and optical activity of the synthesized compounds indicated that L-proline as a catalyst is responsible for the observed enantioselectivity in the studied reactions.

【 授权许可】

CC BY   
© 2012 by the authors; licensee MDPI, Basel, Switzerland.