Effect of Microwaves in the Chiral Switching Asymmetric Michael Reaction
作者:S. Narasimhan、S. Velmathi
DOI:10.3390/80200256
日期:——
HighlyenantioselectiveMichael reactions of malonates with cyclic enones are achieved in remarkably less time under microwave irradiation using newly developed heterobimetallic catalysts.
Helical peptide foldamer catalyzed Michael addition reactions of nitroalkane or dialkyl malonate to α,β-unsaturated ketones are reported along with the mechanistic considerations of the enantio-induction. A wide variety of α,β-unsaturated ketones, including β-aryl, β-alkyl enones, and cyclic enones, were found to be catalyzed by the helical peptide to give Michael adducts with high enantioselectivities
a new lithium-free BINOL-lanthanum complex, which is quite effective in catalyticasymmetricMichaelreaction. We have succeeded in developing effective asymmetric base catalysts, in particular, asymmetric ester enolate catalysts for asymmetricMichaelreactions. Two asymmetric lanthanum complexes are now available, namely, BINOL-lanthanum-lithium complex, which is quite effective in catalytic asymmetric
A new C2-symmetric heterobimetallic complex as a promoter for asymmetric Michael addition reactions
作者:G. Manickam、G. Sundararajan
DOI:10.1016/s0957-4166(97)00234-6
日期:1997.7
C2-symmetric chiral amino diol (1R,5R)-3-aza-3-benzyl-1,5-diphenyl pentan-1,5-diol [(R,R)-I] has been synthesised by a modified procedure. The heterobimetalliccatalyst [I2AlLi] obtained by reaction of the amino diol [(R,R)-I] with LiAlH4, promotes asymmetricMichaeladdition of malonic esters and thiophenols to α,β-unsaturated compounds with high enantiomeric excess.
HighlyenantioselectiveMichaeladdition of malonates to enones catalyzed by dipeptide-derived multifunctional phosphonium salts has been developed. The newly established catalytic system was characterized with its wide substrate scope featured with aliphatic aldehyde-derived enones and substituted malonates. The gram scale-up synthesis of adducts can also be successfully achieved under optimal conditions