The aldol reaction of substituted cyclopentane carbaldehydes with 2‐heptanone. A novel approach to the construction of the alkyl side chain of prostaglandins

Abstract

AbstractThe aldol reaction of suitably substituted cyclopentane carbaldehydes (1a–c, 4) with 2‐heptanone affords β‐hydroxy ketones (2a–c, 5) in yields up to 60%. These aldolization products can be dehydrated to known prostaglandin intermediates. Due to the difficulty to convert β,δ‐dihydroxy ketones selectively into α,β‐unsaturated δ‐hydroxy ketones this reaction sequence for the construction of the (E)‐3‐oxooct‐1‐enyl side chain of prostaglandins seems to be especially advantageous for the synthesis of 11‐deoxy‐prostaglandins.