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.
photoepoxidation of α,β-unsaturated ketones driven by visible light in the presence of tetramethylguanidine (3b), tetraphenylporphine (H2TPP), and molecular oxygen under mild conditions was revealed. The corresponding α,β-epoxy ketones were obtained in yields of up to 94% in 96 h. The reaction time was shortened to 4.6 h by flow synthesis. The mechanism related to singlet oxygen was supported by experiments
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.
and styrenes with molecular oxygen, visible light, and molecular iodine. This procedure involves simultaneous aerobic photooxidative transformation of a benzyl alcohol into a benzaldehyde and of a styrene into a phenacyl iodide, with a subsequent Darzens reaction in one pot. This is the first report of a one-pot oxidative Darzens reaction starting from benzyl alcohols and styrenes. We report a one-pot