Unusual Tandem Oxidative C–C Bond Cleavage and Acetalization of Chalcone Epoxides in the Presence of Iodine in Methanol
作者:Shriniwas Samant、Balaso Jadhav
DOI:10.1055/s-0033-1339134
日期:——
of chalcone epoxides is observed where chalcone epoxides on heating with iodine in methanol leads to α,α-dimethoxyacetophenones, through C–C bondcleavage followed by acetalization of the formyl group. The process occurs through ring opening of the chalcone epoxide by methanol to form β-methoxy alcohol, cleavage of the C–C bond in the latter to form α-ketoaldehyde, and acetalization of the formyl group
Catalytic enantioselective reactions. Part 16. Oxazaborolidine-catalyzed asymmetric borane reduction of α-keto acetals
作者:Byung Tae Cho、Yu Sung Chun
DOI:10.1039/a903335a
日期:——
Asymmetricreductions of α-keto acetals using various oxazaborolidines and borane reagents as catalyst and the hydride source, respectively, were compared. The reduction catalyzed by Corey’s CBS reagents with N-phenylamine–borane reagents provided α-hydroxy acetals with very high enantioselectivities for most aromatic analogues.