Synthesis of 3-Pyrrolines, Annulated 3-Pyrrolines, and Pyrroles from α-Amino Allenes
摘要:
[GRAPHICS]alpha -Amino allenes, readily prepared from reaction of alpha-(N-carbamoyl)alkylcuprates with propargyl substrates followed by N-Boc deprotection, are converted in high yields to pyrrolines with AgNO3. Palladium-catalyzed cyclization of amino allenes affords either the pyrroline or the pyrrole depending on reaction conditions and provides for introduction of an aryl substituent at the C-3 position of the pyrroline or pyrrole. Enantioenriched pyrrolines are readily prepared from scalemic propargyl alcohols.
Reaction of α-(<i>N</i>-Carbamoyl)alkylcuprates with Enantioenriched Propargyl Electrophiles: Synthesis of Enantioenriched 3-Pyrrolines
作者:R. Karl Dieter、Ningyi Chen、Vinayak K. Gore
DOI:10.1021/jo061442h
日期:2006.11.1
Enantioenriched propargyl mesylates or perfluorobenzoates react with α-(N-carbamoyl)alkylcuprates to afford scalemic α-(N-carbamoyl) allenes which undergo N-Boc deprotection and AgNO3-promoted cyclization to afford N-alkyl-3-pyrrolines. The synthetic sequence proceeds under optimal conditions with no loss of enantiopurity relative to the starting propargyl alcohols prepared by asymmetric addition of