Biomimetic hydrogenation: a reusable NADH co-enzyme model for hydrogenation of α,β-epoxy ketones and 1,2-diketones
摘要:
A biomimetic method has been developed to transform alpha,beta-epoxy ketones or 1,2-diketones into corresponding beta-hydroxy ketones or alpha-hydroxy ketones using a catalytic amount of BNAH or BNA(+)Br(-). The regeneration of BNAH or BNA(+)Br(-) is achieved by a mixture of HCOOH/Et3N. A radical mechanism is proposed to explain these observations. (C) 2013 Elsevier Ltd. All rights reserved.
Darzens Reaction Rate Enhancement Using Aqueous Media Leading to a High Level of Kinetically Controlled Diastereoselective Synthesis of Steroidal Epoxyketones
作者:Bo Li、Chunbao Li
DOI:10.1021/jo501500v
日期:2014.9.5
been used in aqueous Darzensreactions. The Darzensreactions were much faster in water than in organic solvents. This aqueous rate enhancement occurred for Darzensreactions between enantiopure steroidal haloketones and aldehydes, yielding enantiopure spiroepoxides with a high level of kinetically controlled diastereoselectivity. Chromatography was avoided in the purifications of the steroidal spiroepoxides
A highly efficient catalytic kinetic resolution of 2,3-epoxy 3-aryl ketones via asymmetric ring-opening with pyrazole derivatives has been achieved by using a chiral N,N′-dioxide–Sc(iii) complex as the catalyst.
Selectfluor-Mediated Simultaneous Cleavage of C–O and C–C Bonds in α,β-Epoxy Ketones Under Transition-Metal-Free Conditions: A Route to 1,2-Diketones
作者:Heng Wang、Shaobo Ren、Jian Zhang、Wei Zhang、Yunkui Liu
DOI:10.1021/acs.joc.5b00857
日期:2015.7.2
Selectfluor-mediated simultaneous cleavage of C–O and C–C bonds in α,β-epoxyketones has been successfully achieved under transition-metal-free conditions. The reaction gives 1,2-diketone compounds in moderate to good yields involving a ring-opening/benzoyl rearrangement/C–C bond cleavage sequence under oxidative conditions.
range of chiral quinazolinol ligands were efficiently synthesized and subsequently investigated for catalyticchiral induction in both the asymmetric phenylation of arylaldehydes and the asymmetric epoxidation of chalcones. Encouragingly, high enantioselectivities (up to 95%) and yields (up to 98%) were achieved under the optimized reaction conditions. A range of chiral quinazolinol ligands were efficiently