Abstract
With Grignard reagent, five-membered vinylogous esters gave 1, 2-addition products in a similar fashion to the cases for six-membered vinylogous esters. On the other hand, the six-membered vinylogous ester substituted with t-butyl group at the α-position of carbonyl function also gave only 1, 2-addition product. However the five-membered vinylogous ester substituted with hydroxy group at the α-position of methoxy group gave 1, 2-addition product and 1, 4-addition products. In these Grignard reactions, the catalytic effect of cuprous chloride was scarcely observed.
