Organocatalytic Formal (3 + 2) Cycloaddition toward Chiral Pyrrolo[1,2-a]indoles via Dynamic Kinetic Resolution of Allene Intermediates

• DOI: 10.1021/acs.orglett.0c01812
• Publication Date: 2020-06-29T23:52:45Z
• Authors: Jian-Fei Bai; Lulu Zhao; Fang Wang; Fachao Yan; Taichi Kano; Keiji Maruoka; Yuehui Li
• Keywords: Stereocenter; Allene; Kinetic resolution; Functional group; Phosphoric acid

We report the chiral phosphoric acid catalyzed formal (3 + 2) cycloaddition of 3-substituted 1H-indoles and propargylic alcohols containing a functional directing group (p-NHAc or p-OH). This work represents straightforward method to synthesize pyrrolo[1,2-a]indole bearing tetrasubstituted carbon stereocenter. The reaction proceeds smoothly with wide array substrate tolerance deliver various pyrrolo[1,2-a]indoles in up 93% yield 98% ee. utility this is highlighted by diverse transformations products into indole derivatives.