Lactams Palladium acetate-Triphenylphosphine

The insertion of carbon monoxide into readily available 2-bromo-3-aminopropene derivatives can be effected by catalytic quantities of palladium acetate and triphenylphosphine high CO pressures are not required (Scheme 16).38 The /Mactam products presumably arise by palladation,carbonylation, and cyclization as depicted in Scheme 17.38 An extension of this approach to the synthesis of biologically interesting condensed /(-lactams can be expected. 

It has been shown that combination of bromoallylation reaction and Heck cyclization is a useful methodology for the preparation of a variety of fused bicyclic (3-lactams of nonconventional structure [95], Starting from acetates 164 and using palladium acetate as the palladium source, DMF as solvent, potassium carbonate as base, and triphenylphosphine, the reaction occurred. The reaction conditions were further optimized and typical results for the preparation of bicyclic (3-lactams 165-168 are summarized in Schemes 57. 

Cyclization of halogenoaryl-substituted /3-lactams can be mediated by palladium(n) derivatives. The formation of the lactam from a ketene-imine addition and subsequent cyclization of the product can be carried out as a one-pot process. As an example, in situ generation of the ketene from the acid chloride and formation of the /3-lactam followed by addition of palladium(ll) acetate, triphenylphosphine, and thalium carbonate gave 495 in 54% yield (Equation 79) <1995TL9053>. 

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See also in sourсe #XX -- [ ]

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