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Regio- and Diastereoselective Dimerization of Diazo Carbonyls: A?Cooperative Catalytic Approach to Complex Scaffolds with Four Contiguous Stereocenters.

ABSTRACT: Starting from readily available o-diazoacyl-substituted arene carboxylates, scaffolds with the 5,9-epoxycyclohepta[b]pyran-2(3H)-one core were obtained by cooperative RhII , Lewis and Brønsted acid catalysis. Four new bonds, three functional groups (lactone, ketal, and alcohol) and four contiguous stereocenters are formed during this regio- and diastereoselective process in a single synthetic step. Intensive optimization and mechanistic studies, including the trapping, isolation, and elucidation of reaction intermediates, led to a plausible mechanistic scenario. The reaction is proposed to involve carbonyl ylides but also transient species of the ketocarbene equilibrium that undergo a cascade of cycloaddition and skeletal rearrangements.

SUBMITTER: Petzold M

PROVIDER: S-EPMC7497023 | biostudies-literature | 2020 Apr

REPOSITORIES: biostudies-literature

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Regio- and Diastereoselective Dimerization of Diazo Carbonyls: A Cooperative Catalytic Approach to Complex Scaffolds with Four Contiguous Stereocenters.

Petzold Martin M Günther Andre A Jones Peter G PG Werz Daniel B DB

Chemistry (Weinheim an der Bergstrasse, Germany) 20200804 49

Starting from readily available o-diazoacyl-substituted arene carboxylates, scaffolds with the 5,9-epoxycyclohepta[b]pyran-2(3H)-one core were obtained by cooperative Rh<sup>II</sup> , Lewis and Brønsted acid catalysis. Four new bonds, three functional groups (lactone, ketal, and alcohol) and four contiguous stereocenters are formed during this regio- and diastereoselective process in a single synthetic step. Intensive optimization and mechanistic studies, including the trapping, isolation, and ...[more]

PMID: 32237096

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