1,2-Vinyl and 1,2-Acetylenyl Migration in Rh(II) Carbene Reaction: Remarkable Bystander Effect

A series of β-(trichloroacetyl)amino α-diazo carbonyl compounds have been synthesized, and their
Rh(II)-catalyzed reaction was investigated. 1,2-Migration was the predominant reaction pathway,
and the migratory aptitude was found to be dramatically affected by the β-substituents. The 1,2-vinyl and 1,2-acetylenyl group migration occurs preferentially in the presence of β-hydrogen in
Rh2(OAc)4-catalyzed reaction of β-(trichloroacetyl)amino α-diazo carbonyl compounds. A possible
reaction mechanism is discussed.