Herein we report the enantioselective N-heterocyclic carbene catalyzed (4+2) annulation of the dienyl acyl azolium with enolates. The reaction exploits readily accessible acyl fluorides and TMS enol ethers to give a range of highly enantio- and diastereo-enriched cyclohexenes (most >97:3 er and >20:1 dr). The reaction was found to require high nucleophilicity NHC catalysts with mechanistic studies supporting a stepwise 1,6-addition/β-lactonization.
While the enantioselective Rauhut–Currier reaction is established with bis(enone) substrates, it is yet to be reported with less electrophilic bis(enoate) substrates. By exploiting high‐nucleophilicity N‐heterocyclic carbenes, it is possible to achieve Rauhut–Currier reactions with these substrates. The reaction is demonstrated with a range of intramolecular reactions (20 examples) and six esterification/RC reaction cascades, which all proceed with high enantioselectivity (most >93:7 er).
While the enantioselective Rauhut-Currier reaction is established with bis(enone) substrates,itisyet to be reported with less electrophilic bis(enoate) substrates.B ye xploiting high-nucleophilicity N-heterocyclic carbenes,i ti sp ossible to achieve Rauhut-Currier reactions with these substrates.T he reaction is demonstrated with ar ange of intramolecular reactions (20 examples) and six esterification/RC reaction cascades,w hich all proceed with high enantioselectivity (most > 93:7 er).
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