Organocatalytic Asymmetric One-Step Desymmetrizing Dearomatization Reaction of Indoles: Development and Bioactivity Evaluation.

An organocatalytic one-step desymmetrizing dearomatization reaction of indoles with in situ formed vinylidene ortho-quinone methide (VQM) is reported. A set of [6-6-5] and/or [5-6-5] fused indoline heterocycles were obtained in excellent yields with excellent diastereoselectivities (>20:1 dr) and enantioselectivities (up to 99% ee). Moreover, some of the obtained products were screened against a panel of cancer cell lines, and 2s was identified to inhibit the proliferation of all the tested cancer cells, but showed the marginal effect against non-cancerous cells. The methodology provides a platform for the synthesis of new leading compounds with antitumor activity.