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Enantioselective synthesis of 3,4-chromanediones via asymmetric rearrangement of 3-allyloxyflavones.

ABSTRACT: Asymmetric scandium(III)-catalyzed rearrangement of 3-allyloxyflavones was utilized to prepare chiral, nonracemic 3,4-chromanediones in high yields and enantioselectivities. These synthetic intermediates have been further elaborated to novel heterocyclic frameworks including angular pyrazines and dihydropyrazines. The absolute configuration of rearrangement products was initially determined by a nonempirical analysis of circular dichroism (CD) using time-dependent density functional theory (TDDFT) calculations and verified by X-ray crystallography of a hydrazone derivative. Initial studies of the mechanism support an intramolecular rearrangement pathway that may proceed through a benzopyrylium intermediate.

SUBMITTER: Marie JC

PROVIDER: S-EPMC2896495 | biostudies-literature | 2010 Jul

REPOSITORIES: biostudies-literature

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Enantioselective synthesis of 3,4-chromanediones via asymmetric rearrangement of 3-allyloxyflavones.

Marié Jean-Charles JC Xiong Yuan Y Min Geanna K GK Yeager Adam R AR Taniguchi Tohru T Berova Nina N Schaus Scott E SE Porco John A JA

The Journal of organic chemistry 20100701 13

Asymmetric scandium(III)-catalyzed rearrangement of 3-allyloxyflavones was utilized to prepare chiral, nonracemic 3,4-chromanediones in high yields and enantioselectivities. These synthetic intermediates have been further elaborated to novel heterocyclic frameworks including angular pyrazines and dihydropyrazines. The absolute configuration of rearrangement products was initially determined by a nonempirical analysis of circular dichroism (CD) using time-dependent density functional theory (TDDF ...[more]

PMID: 20527786

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