Synthesis of 2H-Chromenes via Hydrazine-Catalyzed Ring-Closing Carbonyl-Olefin Metathesis.

ABSTRACT: The catalytic ring-closing carbonyl-olefin metathesis (RCCOM) of O-allyl salicylaldehydes to form 2H-chromenes is described. The method utilizes a [2.2.1]-bicyclic hydrazine catalyst and operates via a [3+2]/retro-[3+2] metathesis manifold. The nature of the allyl substitution pattern was found to be crucial, with sterically demanding groups such as adamantylidene or diethylidene offering optimal outcomes. A survey of substrate scope is shown along with a discussion of mechanism supported by DFT calculations. Steric pressure arising from syn-pentane minimization of the diethylidene moiety is proposed to facilitate cycloreversion.

SUBMITTER: Zhang Y 

PROVIDER: S-EPMC8172096 | biostudies-literature | 2019 Oct

REPOSITORIES: biostudies-literature