posted on 2013-04-05, 00:00authored byXiao-Nan Zhang, Min Shi
4,4-Dicyano-2-methylenebut-3-enoates
are employed in the phosphine-catalyzed [3 + 2] cycloaddition with
allenoates for the first time, affording regiospecific [3 + 2]-annulation
products in moderate to good yields. The multifunctional chiral thiourea-phosphines
having an axially chiral binaphthyl scaffold are effective catalysts
for the asymmetric variant of this reaction, giving the α-regioisomers
in good yields and moderate enantioselectivities.