©2003 Marcel Dekker, Inc. All rights reserved. This material may not be used or reproduced in any form without the express written permission of Marcel Dekker, Inc. MARCEL DEKKER, INC. • 270 MADISON AVENUE • NEW YORK, NY 10016 SYNTHETIC COMMUNICATIONS Õ Vol. 33, No. 13, pp. 2187–2196, 2003 Solvent Effect in the Wittig Reaction Under Boden’s Conditions Enrique M. Pandolfi, * Gloria V. Lo´pez, Eduardo Dı´as, and Gustavo A. Seoane Departamento de Quı´mica Orga´nica, Facultad de Quı´mica, Universidad de la Repu´blica, Montevideo, Uruguay ABSTRACT An interesting change in the stereochemical outcome of the Wittig olefination reaction under Boden’s conditions (potassium bases and 18-crown-6 as the ylide forming reagent) is reported. This effect depends significantly on the polarity of the solvents and the nature of the ylide. Key Words: Stereochemical control; Wittig olefination. *Correspondence: Enrique M. Pandolfi, Departamento de Quı´mica Orga´nica, Facultad de Quı´mica, Av. Gral. Flores 2124, 11800, Universidad de la Repu´blica, Montevideo, Uruguay; E-mail: epandolf@fq.edu.uy. 2187 DOI: 10.1081/SCC-120021496 0039-7911 (Print); 1532-2432 (Online) Copyright & 2003 by Marcel Dekker, Inc. www.dekker.com