Highly Enantioselective Michael Addition of Ketone to Alkylidene Malonates Catalyzed by Binaphthyl Sulfonimides in Water

Abstract

Binaphthyl sulfonimides have been developed to catalyze the asymmetric Michael addition of ketone to alkylidene malonates, affording the corresponding Michael products in good to high yields (up to 98%) with good to excellent diastereoselectivity (up to 99:1 dr) and enantioselectivity (up to 92% ee) under mild conditions using environmentally benign water as the solvent.

Stereoselective conjugate addition of ketones to alkylidene malonates using thiourea‐sulfonamide organocatalyst

“…In 2001, Barbas and coworkers reported the first asymmetric conjugate additions of ketones to alkylidene malonates in moderate to good enantioselectivities using pyrrolidine‐based organocatalyst . Some groups demonstrated the asymmetric Michael addition of ketones to alkylidene malonates using pyrrolidine‐derived urea or thiourea catalyst and sulfonamide organocatalysts . On the contrary, Wang et al reported a thiourea‐sulfonamide organocatalyst that rapidly promoted the conjugate addition of 1,3‐diketones to nitroalkenes.…”

“…33,34 Some groups demonstrated the asymmetric Michael addition of ketones to alkylidene malonates using pyrrolidine-derived urea or thiourea catalyst and sulfonamide organocatalysts. [35][36][37][38][39][40] On the contrary, Wang et al 41 reported a thiourea-sulfonamide organocatalyst that rapidly promoted the conjugate addition of 1,3-diketones to nitroalkenes. Thiourea-sulfonamide organocatalysts bearing multiple hydrogen bonding donors were able to efficiently accelerate asymmetric reactions, improving yields and enantioselectivities.…”

Analysis ofSaussureaspecies from tibet using HPLC-DAD-ESI-MSn

“…HPLC methods for quantitative analysis of S. tridactyla [7] and chemical constituents identified in S. tridactyla [8][9][10], S. medusa [11][12][13][14], S. gossypiphora [15][16][17], and S. laniceps [18,19] are well documented. There is, however, little information about S. aster, S. simpsoniana, S. kingii, and S. quercifolia.…”