Functionalized enamines—XIV

Enamine Ia , derived from 6-methoxy-1-tetralone and morpholine, reacts with carbenes 1 2a and 2b to give (1:1) adducts 3a , and a mixture of 3b and 3c , respectively. The pyrrolidine enamine 1b , on the other hand, reacts with carbene 2b , to give, beside the (1:1) adduct 3e , benzylidene-derivative 4b . Reaction of enamine 1b with carbene 2a does not yield a 1:1 adduct; instead, two products were isolated which have been identified as 4a and 5 . Both morpholine and pyrrolidine enamines 1ab , react with carbene 2c to give one and the same product 6. Possible mechanisms for the formation of the reaction products are discussed.