Cu-Catalyzed Direct Enantioselective Vinylogous Mannich Reaction between β,γ-Unsaturated Pyrazoleamides and Ketimines

Abstract

A catalytic asymmetric vinylogous Mannich-type reaction between β,γ-unsaturated amides and ketimines has been developed in excellent regio-, diastereo-, and enantioselectivities. The methodology provides an efficient approach to construct chiral homoallylic amines with a 3-amino-2-oxindole scaffold. Moreover, the transformations of the chiral products, including the removal of the pyrazole group or Boc group, the reduction of the C−C double bond, and Suzuki coupling, have been investigated.

Enantioselective vinylogous aldol reaction between β,γ-unsaturated amides and isatins

“…3 In this decade, β,γ-unsaturated pyrazoleamides have been applied as γ-nucleophiles in organocatalytic enantioselective vinylogous reactions including aldol-cyclization, 2,4 vinylogous Michael reaction 5 and vinylogous Michael-cyclization. 4 c ,6 Moreover, α,β- and β,γ-unsaturated pyrazoleamides have been applied as γ-nucleophiles in transition-metal-catalyzed enantioselective vinylogous Mannich reaction 7 and amination. 8 However, there is no report on their use in the asymmetric vinylogous aldol reaction without a tandem cyclization process.…”