Development of a triply convergent aldol approach to prostanoids
摘要:
Various organocopper-mediated methods for the conjugate addition of alkyl and alkenyl groups to enone 1 to provide cyclopentanones 4 were studied. A variety of aldol-based procedures for the production of ketones 3 was evaluated, including a two-pot procedure involving generation of lithium enolates from 4, one-pot conjugate additions/aldol condensations methods, and methods involving the intermediate production of silyl enol ethers. The most promising procedure was found to be that involving trapping of the initial enolates from 1 as enol acetates and regeneration of enolates with methyllithium followed by aldol and dehydration reactions.