Asymmetric 1,​4-​Michael Addition in Aqueous Medium Using Hydrophobic Chiral Organocatalysts

DOI : https://doi.org/10.1021/acs.joc.1c00124

Abstract: Org. transformations exclusively in water as an environmentally friendly and safe medium have drawn significant interest in the recent years. Moreover, transition metal-​free synthesis of enantiopure mols. in water will have a great deal of attention as the system will mimic the natural enzymic reactions. In this work, a new set of proline-​derived hydrophoborganocatalysts have been synthesized and utilized for asym. Michael reactions in water as the sole reaction medium. Among the various catalysts screened, the catalyst 1 is indeed efficient for stereoselective 1,​4-​conjugated
Michael addns. (dr: >97:3, ee up to >99.9​%) resulting in high chem. yields (up to 95​%) in a very short reaction time (1 h) at room temp. This methodol. provides a robust, green, and convenient protocol and can thus be an important addn. to the arsenal of the asym. Michael addn. reaction. Upon successful implementation, the present strategy also led to the formation of an optically active octahydroindole, the key component found in many natural products.

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Authors: Chandan K Mahato (TCGLS Member); Satan Mukherjee, Mrinalkanti Kundu* (TCGLS Member); Virbhadra P. Vallapure, Animesh Pramanik