REACTIVE & FUNCTIONAL POLYMERS ELSEVIBR Reactive & Functional Polymers 37 (1998) 283-287 Short communication Enantiopure N-sulfonylamino alcohols and their copolymers as chiral auxiliaries for the highly enantioselective allylboration of aldehydes ’ Shinichi Itsuno a,* , Ashraf A. El-Shehawy a2, Ali A. Sarhan b a Department of Materials Science, Toyohashi University of Technology, Tempaku-cho, Toyohashi 441-8580, Japan b Chemistry Department, Faculty of Science, Mansoura University, Mansoura, Egypt Received 18 June 1997; revised version received 22 July 1997; accepted 25 July 1997 Abstract Enantioselective synthesis of homoallylic alcohols by nucleophilic addition of chirally modified allylboron reagents to aldehydes was investigated. Reaction of enantiopure N-sulfonylamino alcohols (la, lb, 3a, 4a) with triallylborane gave the chiral allylboration reagents. Aldehydes were converted to enantioemiched homoallylic alcohols with the reagents. Polymer-supported chiral allylboron reagents were also prepared from triallylborane and crosslinked polymers having chiral N-sulfonylamino alcohol moieties (5-8). These polymeric reagents reacted with aldehydes to give optically active homoallylic alcohols in high chemical yield with high enantioselectivities. Optical yield up to 92% ee was obtained by the use of polymeric chiral ligand 7 derived from D-camphor. The potential of this type of approach in asymmetric synthesis is discussed. 0 1998 Elsevier Science B.V. All rights reserved. Keywords: Asymmetric allylboration reaction; Polymer-supported reagent; Chid N-sulfonylamino alcohol; Triallylborane 1. Introduction The addition of allylic metal compounds to alde- hydes to yield homoallylic alcohols is a useful trans- formation in organic synthesis and consequently has received considerable attention in recent years [l]. Enantioselective allylation of aldehydes is a direct method for providing optically active homoallylic alcohols. Various chiral allylic metal reagents have been reported for aldehydes allylation [2,3]. Allylic * Corresponding author. ’ This paper is dedicated to Professor Dieter Seebach on the occasion of his 60th birthday. ’ Permanent address: Chemistry Department, Faculty of Educa- tion, Tanta University, Kafr El-She&h, Egypt. organoboranes are particularly versatile members of this class of reagent. The highly enantioselective allylboron reagents have been recently introduced by Brown, Reetz, Roush, Masamune, among others [4-91. However, to our knowledge, no report has appeared where heterogeneous chiral ligands includ- ing crosslinked polymer-supported ones are utilized in the enantioselective allylation of aldehydes. It is always important to develop the polymer-supported reagents or catalysts in organic synthesis since the use of them offers several advantages such as sim- plification of reaction procedures, easy separation of supported species and products, and application to automatic system, etc [ 101. We previously reported enantioselective synthesis of homoallylamines by nucleophilic addition of chirally modified allylboron 1381-5148/98/$19.00 0 1998 Elsevier Science B.V. All rights reserved. PII S1381-5148(97)00117-X