Similar to beta-keto acids; alpha,beta-unsaturated acids also decompose by a cyclic transition state and the loss of CO2. Here the ring/state is 5-membered. Bond breaking and making happens instantaneously, as you'd expect from a transition state.

what is the product A??
http://img266.imageshack.us/i/43982323.png/
Similar to beta-keto acids; alpha,beta-unsaturated acids also decompose by a cyclic transition state and the loss of CO2. Here the ring/state is 5-membered. Bond breaking and making happens instantaneously, as you'd expect from a transition state.
