Organocatalytic asymmetric [3 + 3] annulations of 3-carboxamide oxindoles with β,γ-unsaturated α-keto esters: facile access to chiral spiro-δ-lactam oxindoles

Abstract

We describe here the first organocatalytic asymmetric synthesis of densely functionalized spiro-δ-lactam oxindoles featuring multiple stereogenic centers through a [3 + 3] annulation reaction. This protocol provides a novel, simple and efficient strategy for the synthesis of biologically important spiro-δ-lactam oxindoles using a range of substrates, with excellent diastereoselectivities and enantioselectivities (up to >95 : 5 dr and 99% ee).