Isothiourea-Catalyzed Enantioselective Functionalization of 2-Pyrrolyl Acetic Acid: Two-Step Synthesis of Stereodefined Dihydroindolizinones.
Shuyue ZhangJames E TaylorAlexandra M Z SlawinAndrew David SmithPublished in: Organic letters (2018)
Catalytic enantioselective functionalization of 2-pyrrolyl acetic acid with trichloromethyl enones using isothiourea catalysis is reported, leading to a range of stereodefined diesters and diamides after nucleophilic ring opening with either methanol or benzylamine (30 examples, up to >95:5 dr and >99:1 er). Subsequent intramolecular Friedel-Crafts reaction allows access to dihydroindolizinones in high yields and stereofidelity (6 examples, up to >95:5 dr and 99:1 er).