52411-65-1Relevant academic research and scientific papers
Unexpected steric effects of "remote" alkyl groups on the rate of conjugate additions to alkyl α,β-ethylenic sulfones, sulfoxides, and esters
Usera, Aimee R.,Posner, Gary H.
, p. 2329 - 2334 (2007)
Examination of conjugated ethylenic sulfones, sulfoxides, and esters in Michael-type addition reactions reveals, for the first time, that the size of the heteroatom-attached alkyl group affects the rate of conjugate addition. Molecular modeling strongly suggests that what are generally considered to be "remote" alkyl groups in -CβH=CαHS(O) n,-alkyl systems and -CH2CβH=C αHCOO-alkyl systems are actually not remote from the β-carbon atom of the Michael accepting unit. Molecular modeling clearly shows that the alkyl groups in these Michael acceptors shield the β-carbons in the following order: Et i-Pr > t-Bu.
