Catalytic Asymmetric Synthesis of Dihydropyrido[1,2‐<i>a</i>]indoles from Nitrones and Allenoates

Abstract

Abstract An asymmetric method for the synthesis of dihydropyrido[1,2‐ a ]indoles from mixtures of nitrones and allenoates has been developed. This transformation showcases the use of squaramide catalysis in a complicated cascade system that has been shown to be highly sensitive to reaction conditions and substituent effects. The new method provides access to enantiomerically enriched dihydropyridoindoles from modular, non‐indole reagents. The optimization and scope of the new transformation is discussed in addition to initial mechanistic experiments that indicate the role of the catalyst.