Asymmetric phase-transfer Mannich-type

Catalytic Asymmetric Phase-Transfer Mannich-Type Reaction... 

Scheme 6.5 Catalytic asymmetric phase-transfer Mannich-type reaction.

Shibuguchi T, Mihara H, Kuramochi A, Ohshima T, Shibasaki M (2007) Catalytic Asymmetric Phase-Transfer Michael Reaction and Mannich-Type Reaction of Glycine SchiffBases with Tartrate-Derived Diammonium Salts. Chem Asian J 2 794... 

Shibuguchi T, Mihara H, Kuromachi A, Ohshima T, Shibasaki M. Catalytic asymmetric phase-transfer Michael reaction and Mannich-type reaction of glycine Schiff gases with tartrate-derived diammonium Salts. Chem. Asian J. 2007 2(6) 794-801. 

Mannich-type reactions are another important class of transformations that have very successfully been carried out using asymmetric phase-transfer... 

With respect to the application of tartaric acid-derived PTCs [22,23] for natural product synthesis, the work of Shibasaki s group should be highlighted herein. Using his powerful bidentate TaDiAS PTCs, asymmetric phase-transfer-catalyzed alkylations, Michael addition reactions, and Mannich-type reactions have been systematically carried out. 

Catalytic Asymmetric Mannich-Type Reaction under Solid/Liquid Phase Transfer Conditions [11] (p. 146)... 

Abstract The organocatalytic asymmetric Mannich reaction and the related aza-Morita-Baylis-Hillman have been reviewed. The activities in this field have been snbdivided based on the types of catalysts that have been ntilized, which includes catalysis by enamine-forming chiral amines, chiral Br0nsted bases, chiral Brpnsted acids, and phase-transfer catalysts. 

Using a similar concept, Shibasaki and co-workers [93] also reported an asymmetric Mannich-type reaction of Schiff base 245 with alkyl imine 246 catalyzed by phase-transfer catalyst 239 for the total synthesis of (-t-)-nemonapride (249) (Scheme 17.42). In this synthesis, the key intermediate 247 was converted to pyrrolidine derivative 248 after two steps (>99% ee after recrystallization), which was easily transformed into (+)-nemonapride (249) via reduction and coupling reaction. 

The asymmetric synthesis of nemonapride 92 was achieved by applying the Mannich-type reaction of the Schiff base 1 with A-Boc aliphatic imine 93 under the phase-transfer catalysis of (S,S)-TaDiAS (PTC 11) (Scheme 4.22)." The differently protected a,(3-diamino acid ester 94 was isolated in 72% yield with 65% ee, which was then transformed into the stereochemicaUy pure pyrrolidine derivative 95, an important precursor of the target 92. 

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