Cyclization Forming Lactones and Lactams

A similar protocol can be extended to a wider range of lactams than lactones (Tab. 6.6), although an electron-withdrawing substituent on the amino nitrogen is required for selective formation of a yS-lactam from sterically less-constrained propargyhc 

A novel route was examined for the synthesis of the u,y9-unsaturated amide 59 vio the intermolecular couphng of four components an alkyne, a hydrosilane, an amine, and CO (Eq. 11). All of these components are assembled in an ordered manner with the assistance of a rhodium complex. The use of pyrrolidine as the nucleophile gave the optimum results, whereas alcohols were not reactive nucleophiles under similar reaction conditions [19 ej. 

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