Platinum complexes aldol reaction

Aldol reactions of isocyanides with aldehydes are catalyzed by cationic platinum complexes having P-C-P or N-C-N ligands in the presence of a catalytic amount of an amine base to give 2-oxazolines (Equation (126)) 48S>485a>485b Platinum-coordinated a-isocyano carbanions presumably serve as nucleophiles toward aldehydes. Low to moderate enantioselectivities were obtained by using chiral platinum complexes.485 4853... 

The use of chiral platinum complex as Lewis acid catalysts for the aldol reaction has been documented and studied by several groups. The platinum catalysts are generated upon the treatment of platinum salts and phosphines in generally. The PCP-type chiral platinum complexes 31 have been shown to function effectively in the aldol addition of methyl isocyanoacetate and aldehydes in excellent yields and promising enantioselectivities (Scheme 9) (78-80). The first... 

Chiral bis-phosphine acylplatinum complex 210 with a strong acid such as TfOH serves as an effective enantio-selective catalyst for aldol-type reactions of aldehydes with ketene silyl acetals (Equation (127)).486 The presence of water and oxygen in the catalyst preparation step is required to obtain the highly enantioselective catalyst. The intermediacy of a C-bound platinum enolate was suggested by IR and 31P NMR spectroscopies. 

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