molecules

Organocatalysis in synthesis: L-Proline as an enantioselective catalyst in the synthesis of pyrans and thiopyrans

NMH Elnagdi, NS Al-Hokbany

Index: Hilmy Elnagdi, Noha M.; Al-Hokbany, Noura Saad Molecules, 2012 , vol. 17, # 4 p. 4300 - 4312

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Citation Number: 31

Abstract

Abstract: 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, ee and optical activity of the synthesized compounds indicated that L- ...