A Catalytic Asymmetric Hydrolactonization.

Despite recent advancements in the development of catalytic asymmetric electrophile induced lactonization reactions of olefinic carboxylic acids, the archetypical hydrolactonization has long remained an unsolved and well-recognized challenge. Here, we report the realization of a catalytic asymmetric hydrolactonization using a confined imidodiphosphorimidate (IDPi) Brønsted acid catalyst. The method is operationally simple, scalable, and compatible with a wide variety of substrates. Its potential is showcased with concise syntheses of the sesquiterpenes (-)-boivinianin A and (+)-gossonorol. Through in-depth physicochemical and DFT analyses, we derive a nuanced picture of the mechanism and enantioselectivity of this reaction.