ylides derived from short-chain trialkylphosphines in the Wittig-type olefinationreactions toward the synthesis of alkenes, including stilbenes, styrenes, and 1,3-dienes, as well as reagents for homologation reactions, are described. The methods allow easy access to alkenes with high (E)-stereoselectivity in good yield. These reactions are conducted with weak bases in aqueous media, which allows easy
Stereoselective Synthesis of the Antileukemic Sesquiterpene (+)-Caparratriene from L-menthol and Tiglic Aldehyde
作者:V. A. Vydrina、A. A. Kravchenko、M. P. Yakovleva、N. M. Ishmuratova、G. Yu. Ishmuratov
DOI:10.1007/s10600-018-2379-y
日期:2018.5
A stereoselectivesynthesis of natural (+)-caparratriene was developed starting from commercially available L-menthol and tiglic aldehyde. The key step was a Wittig reaction of the latter with the triphenylphosphorane generated from (R)-(–)-citronellyl bromide. (+)-Caparratriene as a mixture (4:1) of 2E,4E- and 2E,4Z-stereoisomers is a known anticancer agent.
A short synthesis of the anti-leukemic sesquiterpene (+)-caparratriene employing aqueous Wittig chemistry
作者:Priyabrata Das、James McNulty
DOI:10.1016/j.tetlet.2010.04.035
日期:2010.6
An efficient, stereoselective method for the synthesis of (+)-caparratriene based on an aqueous Wittig reaction has been developed. A functionalized triethylallyl ylide reacted under various conditions with (+)-citronellal to deliver (+)-caparratriene in only three steps with excellent overall yield. The Wittig reaction proceeded with exclusive (4E)-selectivity and an interesting cationic effect was uncovered with good stereoselectivity at the isomerizable allylic position being observed in the presence of lithium salts. (C) 2010 Elsevier Ltd. All rights reserved.