2,4,4,6-Tetrabromo-2,5-cyclohexadienone (TABCO), N-Bromosuccinimide (NBS) and Bromine as Efficient Catalysts for Dithioacetalization and Oxathioacetalization of Carbonyl Compounds and Transdithioacetalization Reactions
作者:Nasser Iranpoor、Habib Firouzabadi、Hamid Reza Shaterian、M. A. Zolfigol
DOI:10.1080/10426500211712
日期:2002.5.1
6-tetrabromo-2,5-cyclohexadienone (TABCO), N-bromosuccinimide (NBS), and bromine as efficient catalysts for conversion of carbonyl compounds to their cyclic and acyclic dithioacetals and 1,3-oxathiolanes under mild reaction conditions are described. These catalysts are also used for efficient transdithioacetalization of acetals, diacetals, ketals, acylals, enamines, hydrazones, and oximes with high
Radical-Hydroboration-Involved One-Pot Synthesis of Boron-Handled Glycol Derivatives
作者:Feng-Lian Zhang、Yi-Feng Wang、Bi-Yang Zhuang、Ji-Kang Jin
DOI:10.1055/s-0040-1707142
日期:2021.3
A one-pot two-step protocol for the direct synthesis of boron-handled glycol derivatives is reported. The procedure starts by an NHC–boryl-radical-promoted regioselective hydroboration of glycol-protected cinnamaldehydes. After that, the reaction mixture is treated with pinacol in the presence of HCl, leading to the direct formation of pinacol boronate handled glycol monoalkyl ethers. In this acid-triggered
An Efficient Method for One-Pot Reductive Cleavage of Acetals to Primary Alcohols Using a Bimetal Redox Couple CoCl2.6H2O-Zn
作者:Kuladip Sarma、Amrit Goswami
DOI:10.2174/157017809789869456
日期:2009.10.1
Acyclic or cyclic O,O-acetals and O,S-acetals underwent reductivecleavage to give primary alcohols efficiently on treatment with Zn-CoCl2.6H2O-bimetal redox system in dry tetrahydrofuran at ambient temperature to give good to excellent yields.
Poly(N-bromobenzene-1,3-disulfonamide) and N,N,N′,N′-tetrabromobenzene-1,3-disulfonamide as a mild and efficient catalyst for chemoselective thioacetalization of carbonyl functions and transthioacetalization reactions
Poly(N‐bromobenzene‐1,3‐disulfonamide) and N,N,N′,N′‐tetrabromobenzene‐1,3‐disulfonamide are effective catalysts for chemoselective dithioacetalization of aldehydes in the presence of ketones under neutral conditions. J. Heterocyclic Chem., (2011).
A generalized, simple and efficient transfer hydrogenation of unsaturated bonds has been developed using HBPin and various proton reagents as hydrogen sources. The substrates, including alkenes, alkynes, aromatic heterocycles, aldehydes, ketones, imines, azo, nitro, epoxy and nitrile compounds, are all applied to this catalytic system. Various groups, which cannot survive under the Pd/C/H2 combination
使用HBPin和各种质子试剂作为氢源,已经开发了一种普遍,简单而有效的不饱和键转移加氢方法。包括烯烃,炔烃,芳族杂环,醛,酮,亚胺,偶氮,硝基,环氧和腈化合物在内的所有底物均应用于该催化体系。可以容忍在Pd / C / H 2组合下无法生存的各种基团。研究了反应物的活性,其变化趋势为:苯乙烯>二苯基甲亚胺>苯甲醛>偶氮苯>硝基苯>喹啉>苯乙酮>苄腈。还研究了带有两个或多个不同不饱和键的底物,并以优异的化学选择性发生了转移氢化。由Pd(OAc)2和HBPin生成的二氧化钛极大地提高了TH效率。此外,使用D 2 O和HBPin通过原位HD生成和区分,实现了末端芳族烯烃的化学选择性抗Markovnikov加氢氘。