Enantioselective synthesis of 1,2-dihydronaphthalene-1-carbaldehydes by addition of boronates to isochromene acetals catalyzed by tartaric acid.

ABSTRACT: Tartaric acid is an ideal asymmetric catalyst as it is abundant, cheap, and environmentally friendly. (+)-Tartaric acid was found to catalyze a novel enantioselective [4 + 2] cycloaddition of isochromene acetals and vinylboronates. A variety of substituted isochromene acetals were tolerated, furnishing the desired dihydronaphthalenes and dihydrobenzofluorene products in good yields. High enantiomeric ratios (up to 98.5:1.5) and excellent diastereoselectivities (all >99:1) were observed employing 10 mol % of (+)-tartaric acid as the catalyst, in combination with 5 mol % of Ho(OTf)3.

SUBMITTER: Luan Y 

PROVIDER: S-EPMC4666678 | biostudies-literature | 2015 Mar

REPOSITORIES: biostudies-literature