ChemInform Abstract: Synthesis of Chiral Cyclic Nitrones by Asymmetric Addition of β‐Ketosulfones to Nitroalkenes Followed by Reductive Cyclization.

Abstract

Synthesis of Chiral Cyclic Nitrones by Asymmetric Addition of β-Ketosulfones to Nitroalkenes Followed by Reductive Cyclization. -The addition step is catalyzed by thiourea cinchona alkaloids like (I) to give the sulfone addition products as diastereomeric mixtures. The following reduction step proceeds selectively in the presence of activated zinc/ammonium chloride. The method can be extended to the synthesis of N-hydroxypyrrolidines (VII) bearing a quaternary stereocenter by addition of TmsCN to the C=N bond of the cyclic nitrones in the presence of a Lewis acid. -(GARCIA MANCHENO*, O.; TANGEN, P.; ROHLMANN, R.; FROEHLICH, R.; ALEMAN, J.; Chem. Eur. J. 17 (2011) 3, 984-992, http://dx.