Organocatalytic Domino Oxa‐Michael/1,6‐Addition Reactions: Asymmetric Synthesis of Chromans Bearing Oxindole Scaffolds |
| |
| Authors: | Kun Zhao Dr. Ying Zhi Tao Shu Dr. Arto Valkonen Prof. Dr. Kari Rissanen Prof. Dr. Dieter Enders |
| |
| Affiliation: | 1. Institute of Organic Chemistry, RWTH Aachen University, Aachen, Germany;2. Department of Chemistry, Nanoscience Center, University of Jyvaskyla, JYU, Finland |
| |
| Abstract: | An asymmetric organocatalytic domino oxa‐Michael/1,6‐addition reaction of ortho‐hydroxyphenyl‐substituted para‐quinone methides and isatin‐derived enoates has been developed. In the presence of 5 mol % of a bifunctional thiourea organocatalyst, this scalable domino reaction affords 4‐phenyl‐substituted chromans bearing spiro‐connected oxindole scaffolds and three adjacent stereogenic centers in good to excellent yields (up to 98 %) and with very high stereoselectivities (up to >20:1 d.r., >99 % ee). |
| |
| Keywords: | chromans domino reactions organocatalysis oxa-Michael addition para-quinone methides |
|
|
