ChemInform Abstract: Chiral Phosphine-Catalyzed Tunable Cycloaddition Reactions of Allenoates with Benzofuranone-Derived Olefins for a Highly Regio-, Diastereo- and Enantioselective Synthesis of Spiro-Benzofuranones

The SBIP-catalyzed reaction of benzofuranone alkene (I) with allenes (II) affords γ-addition [3 + 2] cycloadducts (III) with high enantioselectivity, whilst the reaction with allenes (IV) gives rise to α-addition [3 + 2] cycloadducts (V).