Palladium(O)-catalyzed alkylation of various allylic carbonates by aromatic thiols allowed the easy preparation of various allylic aryl sulphides in quite good yields. The reaction was regioselective with substitution at the less hindered side of the π-allyl system whatever the temperature of the reaction, and was diastereoselective with net retention of configuration.
Allyl 2-pyridyl sulfide or allyl phenyl sulfone on treatment with n-butyllithium in tetrahyrofuran followed by tri-n-butylstannylmethyl iodide () afforded directly the 1,3-diene in good yield.
An expedient approach to E,Z-dienes using the Julia olefination
作者:André B Charette、Carl Berthelette、David St-Martin
DOI:10.1016/s0040-4039(01)00941-8
日期:2001.7
New reaction conditions were developed for the synthesis of E,Z-dienes from alpha,beta -unsaturated aldehydes and heteroarylsurfones using the Julia reaction. In most cases under optimal conditions, the selectivity of the olefination reaction is better than 88:12 when a pyridylsulfone was used as the precursor. In addition, novel reaction conditions for the chemoselective oxidation of heteroarylthioethers that are compatible with alkenes and dienes are also reported. (C) 2001 Elsevier Science Ltd. All rights reserved.
Goux Catherine, Lhoste Paul, Sinou Denis, Tetrahedron, 50 (1994) N 34, S 10321-10330