Enamines from Lactams and Grignard Reagents

This method of preparation has been developed primarily by Lukes (103,104). N-Methyl lactams (117) with five- and six-membered rings plus Grignard reagents yield the l-methyl-2-alkyl pyrroUnes (118, = 1) and l-methyl-2-alkylpiperideines(118, n = 2), respectively, plus 2,2-dialkylated bases (119) as by-products (103). For example, l,3-dimethyl-2-piperidone 

This method provides a route to certain medium-ring sized enamines (106,107) not obtainable by other methods, l-Methyl-2-phenyl-l-azacyclo-hcpt-2-ene (124) can be prepared by the reaction of N-methylcaprolactam 

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