Cycloaddition reactions of pyridinium and related azomethine ylides

A Padwa, DJ Austin, L Precedo…

Index: Padwa, Albert; Austin, David J.; Precedo, Laura; Zhi, Lin Journal of Organic Chemistry, 1993 , vol. 58, # 5 p. 1144 - 1150

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Citation Number: 80

Abstract

The Rh (I1)-catalyzed reaction of a-diazoacetophenone in the presence of 24methylthio) pyridine and dimethyl acetylenedicarboxylate gave 3-benzoyl-1, 2-dicarbomethoxy-3, 5- dihydro-5-(methylt~ o)-indolizine. The formation of the cycloadduct proceeds via a pyridinium ylide formed by attack of the nitrogen lone pair on the electrophilic keto carbenoid. A related cyclization occurred using 1-diazo-3-[(2-pyridyl) thiol-2-propanone. ...