Electrophilicities of Bissulfonyl Ethylenes

Kinetics of the reactions of bissulfonyl ethylenes with various carbanions, a sulfur ylide, and siloxyalkenes have been investigated photometrically at 20 degrees C. The second-order rate constants have been combined with the known nucleophile- specific parameters N and sN for the nucleophiles to calculate the empirical electrophilicity parameters E of bissulfonyl ethylenes according to the linear free energy relationship log k(20 degrees C)=sN(N+E). Structure-reactivity relationships are discussed, and it is shown that the electrophilicity parameters E derived in this work can be employed to define the synthetic potential of bissulfonyl ethylenes as Michael acceptors.