Addition of Lithiated 5-Hydroxymethyl-1,3-dithiane to Benzaldehyde: HMPA-Controlled Trans Stereoselectivity
作者:Zaiguo Li、Alexei N. Kurchan、Andrei G. Kutateladze
DOI:10.1021/ol0499497
日期:2004.4.1
Addition of 5-substituted dithianyl anions to carbonyl compounds normally produces trans adducts. The presence of a nucleophilic hydroxymethyl group in position 5 dramatically decreases the trans stereoselectivity of the reaction in THF. The trans/cis ratio shows a bell curve dependence on HMPA, fitted to a quantitative model involving a series of equilibrated ion pairs, of which an intermediate contact
Through the synthesis and study of model systems as proper dithiane derivatives, vinyl monomers and soluble copolymeric reagents containing 2-unsubstituted 1,3-dithiane rings, we attained the key synthon 1,3-dithiane-5-methanol. Through its reaction with commercial resins, new polymericreagents useful for supported organic synthesis and combinatorial chemistry were developed. Exploiting the reactivity