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

Abstract

In this study, stereoselective conjugate addition of ketones to alkylidene malonates using organocatalyst has been developed. The reaction in the presence of 20 mol% of a novel thiourea-sulfonamide organocatalyst afforded conjugate adducts in moderate to high yields (up to 81%) under mild reaction conditions. Excellent diastereoselectivity (up to 98:2 dr) and enantioselectivity (up to 88% ee) were achieved.

Regulated synthesis of Zr-metal–organic frameworks with variable hole size and its influence on the performance of novel MOF-based heterogeneous amino acid–thiourea catalysts

“…In recent years, proline-functionalized MOFs are built on the framework of MIL, 22 UiO, 23 IRMOF, 24 DUT 25 and PCN, 26 but an unsatisfactory enantioselectivity is obtained in heterogeneous asymmetric reaction. 27 Organic chemists have discovered that a chiral catalyst with hydrogen-bond donor motifs associated with complementary functional frameworks such as thiourea oen has high enantioselectivity, 28,29 because of the H-bond donor site anked by sites for secondary interaction with substrates. In our work, proline-thiourea motifs have been rst covalently graed inside MOF cavities by a mild synthesis method, to design a chiral heterogeneous catalyst.…”

“…Organic chemists have discovered that a chiral catalyst with hydrogen-bond donor motifs associated with complementary functional frameworks such as thiourea often has high enantioselectivity, 28,29 because of the H-bond donor site flanked by sites for secondary interaction with substrates. In our work, proline–thiourea motifs have been first covalently grafted inside MOF cavities by a mild synthesis method, to design a chiral heterogeneous catalyst.…”