Organocopper‐Triggered Cyclisation of Conjugated Diene‐ynes: Diastereo‐ and Enantioselective Synthesis of Indenes

Abstract

International audienc

1,3-Dien-5-ynes: Versatile Building Blocks for the Synthesis of Carbo- and Heterocycles

“…Bertrand and Nechab have made use of an organocoppertriggered cyclization to access chiral 3-alkyl indenes with high enantiomeric excesses and moderate to good yields and diastereoselectivities (Scheme 69). 163 The reaction takes place with chirality transfer from enantiomerically enriched o-(alkynyl)chalcones with a propargylic carbonate moiety. The mechanism that accounts for this transformation begins with selective addition of an organocopper reagent to the propargylic carbonate in a S N 2′ fashion, generating an allene intermediate in a process that occurs with central-to-axial chirality transfer.…”

“…163 The reaction takes place with chirality transfer from enantiomerically enriched o-(alkynyl)chalcones with a propargylic carbonate moiety. The mechanism that accounts for this transformation begins with selective addition of an organocopper reagent to the propargylic carbonate in a S N 2' fashion, generating an allene intermediate in a process that occurs with central-to-axial chirality transfer.…”

Organocopper triggered cyclization of conjugated dienynesviatandem SN2′/Alder-ene reaction

“…6,7 This methodology was then implemented to propose a chemo-, diastereo-and enantioselective access to chiral indenes from conjugated dienynes bearing a Michael acceptor (Scheme 1a). 8 Both strategies relied on the use of the stereo-controlled S N 2′ displacement of an enantiopure propargylic carbonate by a dialkylcuprate to generate in situ a transient chiral allenic motif. In line with these studies, it was natural to investigate the scope of the tandem alkylation/Alder-ene rearrangement of dienynes triggered by organocopper reagents as a potential route to isopropenylindenes according to Scheme 1b.…”

Palladium Tandem Catalysis in the Atropodiastereoselective Synthesis of Indenes Bearing Central and Axial Chirality

“…We have been interested in the development of cascade reactions triggered by the formation of a transient allene to build hetero- and carbo-polycyclic frameworks . As recently reported, chiral benzofulvenes and indenes were prepared from diynes and enynes through a strategy using organocopper reagents and implying a double transfer of chirality . The interest of multiple-bond-forming atom-economical processes using transition-metal catalysis for the construction of carbocyclic scaffolds no longer needs to be demonstrated .…”