A three-step synthesis of (2Z), (4E)-polyenic acids 6 is described. Condensation of aldehydes 1 with potassium prenal enolate led to dihydropyranols 3 which were oxidized into dihydropyrones 5, precursors of (2Z), (4E)-polyenic acids 6. The procedure was applied to a synthesis of 13-cis-retinoic acids from beta-ionylidene acetaldehydes. (C) 2000 Elsevier Science Ltd. All rights reserved.
Synthesis of conjugated γ- and δ-lactones from aldehydes and ketones via a vinylation(allylation)-ring closing metathesis–oxidation sequence
作者:J.Alberto Marco、Miguel Carda、Santiago Rodrı́guez、Encarnación Castillo、Marı́a N. Kneeteman
DOI:10.1016/s0040-4020(03)00584-2
日期:2003.6
aldehydes and ketones followed by O-allylation of the obtained carbinols gave the corresponding allyl or homoallyl ethers, respectively. Ring-closing metathesis of these compounds afforded in many cases cyclic ethers (dihydrofurans and dihydropyrans, respectively) bearing disubstituted and trisubstituted CC bonds. These were then subjected to allylic oxidation to yield conjugated γ- and δ-lactones. Reasons
A three-step synthesis of (2Z), (4E)-polyenic acids 6 is described. Condensation of aldehydes 1 with potassium prenal enolate led to dihydropyranols 3 which were oxidized into dihydropyrones 5, precursors of (2Z), (4E)-polyenic acids 6. The procedure was applied to a synthesis of 13-cis-retinoic acids from beta-ionylidene acetaldehydes. (C) 2000 Elsevier Science Ltd. All rights reserved.