Five‐Membered Cyclic Nitronates in C–C Coupling with 1‐(<i>tert</i>‐Butyldimethylsilyloxy)‐1‐methoxyethylene

Abstract

Abstract Five‐membered cyclic nitronates 3 undergo TBSOTf‐catalysed C–C coupling reactions with silyl ketene acetal 4 to give good to excellent yields of 3,3‐disubstituted N ‐(OTBS)‐isoxazolidines 5 , which could not be obtained by previously known procedures. The problems of diastereoselectivity of the C–C coupling reactions are discussed. The transformations of the nitroso acetals 5 upon action of Ac F OH/methanol or some reducing agents (H 2 /Ni Ra , LAH, Al/Hg) have been examined.(© Wiley‐VCH Verlag GmbH &amp; Co. KGaA, 69451 Weinheim, Germany, 2009)