Chromium and tungsten pentacarbonyl groups as reactivity and selectivity auxiliaries in [3+ 2] cycloaddition of alkynyl fischer carbene complexes with N-alkyl nitrones

KS Chan, ML Yeung, W Chan, RJ Wang…

Index: Chan, Kin Shing; Yeung, Ming Lok; Chan, Wai-kin; Wang, Ru-Ji; Mak, Thomas C. W. Journal of Organic Chemistry, 1995 , vol. 60, # 6 p. 1741 - 1747

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Citation Number: 71

Abstract

Alkynyl Fischer carbene complexes were found to undergo chemoselective, regioselective, and rateenhanced 1, 3-dipolar cycloaddition with nitrones to give 2, 3-dihydroisoxazole carbene complexes in excellent yields. These alkynyl complexes can serve as synthons for substituted propiolate esters since the metal pentacarbonyl group of the cycloadducts can be easily oxidatively removed with DMSO. The tungsten carbene complex 4b reacted with ...