Under palladium or nickel catalysis. a stereomeric mixture 1:1 of (Z) and (E)-1,2-dichloroethylene readily reacts with 1-alkynes. vinyl alanes or vinyl boranes to afford selectively the corresponding (E)-coupling product in good to excellent isolated yields. The selectivity of this coupling reaction is discussed. (C) 2002 Elsevier Science Ltd. All rights reserved.
Stereoselective approaches to (E,E,E) and (Z,E,E)-α-chloro-ω-substituted hexatrienes: Synthesis of all E polyenes
palladium-catalyzed rearrangement of bis-allylic acetates 4 and 5 and the second one is based on the stereoselective reduction of homopropargylic alcohols 6 followed by an elimination reaction. These stable chlorotrienes 1–3 are suitable synthetic intermediates for the construction of navenone B and allE polyenes (trienes, tetraenes, hexaenes and heptaenes).
Stereocontrolled synthesis of (E,E,E)-chlorotrienes: Efficient intermediates for the construction of all E conjugated polyenes
作者:Benoit Crousse、Mouâd Alami、Gérard Linstrumelle
DOI:10.1016/s0040-4039(97)01156-8
日期:1997.7
Stereoselective reduction of conjugated homopropargylic alcohols 1 followed by an elimination reaction, allows an efficient approach to stereodefined (E,E,E)-chlorotrienes. The interest of these chlorotrienes was illustrated by a stereocontrolledsynthesis of navenone B and allE conjugated polyenes (trienes, tetraenes and hexaenes).