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.
Development of N,N-bis(perfluoroalkanesulfonyl)squaramides as new strong Brønsted acids and their application to organic reactions
作者:Cheol Hong Cheon、Hisashi Yamamoto
DOI:10.1016/j.tet.2010.03.120
日期:2010.6
l groups have been developed and applied to several organic reactions. These squaramides are bench-stable and exhibit much higher reactivities in several organic reactions than squaric acid itself. N,N-Bis(trifluoromethanesulfonyl)squaramide 2a was applied to the Mukaiyama aldol reaction and Mukaiyama Michael reaction. Mechanistic studies revealed that the Brønsted acid might be the predominant catalyst
By judicious choice of the counter anions in the vanadyl catalysts, we can achieve β-hydroxylated and t-butyl peroxylated carbonylation of styrenes by aromatic 1° and 2° alkyl aldehydes in a complementary manner.
Kinetic Resolution of β-Hydroxy Carbonyl Compounds via Enantioselective Dehydration Using a Cation-Binding Catalyst: Facile Access to Enantiopure Chiral Aldols
作者:Sushovan Paladhi、In-Soo Hwang、Eun Jeong Yoo、Do Hyun Ryu、Choong Eui Song
DOI:10.1021/acs.orglett.8b00547
日期:2018.4.6
β-hydroxy carbonyl (aldol) compounds through enantioselective dehydration process was developed using a cation-binding Song’s oligoethylene glycol (oligoEG) catalyst with potassium fluoride (KF) as base. A wide range of racemic aldols was resolved with extremely high selectivity factors (s = up to 2393) under mild reaction conditions. This protocol is easily scalable. It provides an alternative approach for
administration of cancer chemopreventive agents (CCAs) that prevent, delay or reverse the carcinogenic process. CCAs that are able to induce detoxification enzymes, especially monofunctional phase II enzymes, have become an excellent therapeutic strategy. Herein, we report the synthesis of eighteen new potential CCAs, structurally designed to combine (naphtho)chalcone and (bromo)pyridine skeletons. After a selection
active molecules, synthetic drugs and fine chemicals. Although there are some routes available for their manufacture from pre-functionalized groups on one or two matrix molecule(s), the approaches to simply and simultaneously deposit two oxygen atoms from dioxygen into two specific C(sp3) positions of pure saturated hydrocarbons have rarely succeeded because they are involved in the targeted activation
β-和γ-羟基酮结构都是生物活性分子,合成药物和精细化学品中的重要单元。尽管有一些方法可以从一个或两个基质分子上的预官能团制造它们,但是将双氧中的两个氧原子简单并同时沉积到纯饱和烃的两个特定C(sp 3)位置的方法有很少成功,因为它们一次都参与了三个惰性CHσ键的靶向活化。在这里,我们表明TiO 2 -CH 3 CN光催化悬浮体系能够将双氧插入一个C(sp 3)-C(sp 3)应变环烷烃衍生物的键,通过一锅反应获得双官能化的羟基酮产物。通过裂解事件以释放应变作为方向驱动力,按设计的光催化反应系统显示,三元环衍生物的21个实例的β-羟基酮产物的分离产率为31%-76%,而5个实例的γ-羟基酮产物的分离产率为31%-76%。四元环底物的孤立产率为30%–63%。使用18 O 2,Ti 18 O 2和有意添加的H 2 18进行18 O同位素标记实验O,分别表示的羟基酮产品两个氧原子都完全由双氧,表明先前未知的ħ