Novel Deoxygenation Reaction of Epoxides by Indium
作者:Mohan Mahesh、John A. Murphy、Hans Peter Wessel
DOI:10.1021/jo047904d
日期:2005.5.1
A novel, mild, ecofriendly protocol for the deoxygenation of epoxides to alkenes using indium metal and indium(I) chloride or ammonium chloride in alcohol has been developed. It was necessary for the presence of good radical-stabilizing groups adjacent to the oxirane ring for the deoxygenation reaction to occur. It is proposed that this reaction occurs through an SET process with indium as an electron
An internally activated tin hydride with enhanced reducing ability
作者:E. Vedejs、S. M. Duncan、A. R. Haight
DOI:10.1021/jo00063a024
日期:1993.5
Tin hydride 1 is activated for nucleophilic hydride transfer and also for radical chain reduction, depending on solvent. The nucleophilic hydride pathway is favored in methanol, and 1 can be used as a selective reducing agent for ketones. Simple ketones are not reduced in aprotic solvents, but beta-hydroxy ketones are activated internally by the hydroxyl group and can be reduced in THF with good control of stereochemistry, as in the conversion from 7 to 9 (30:1 9:8). A catalytic version of the nucleophilic hydride reductions in methanol has been developed using PhSiH3 as the stoichiometric hydride source. Radical chain dehalogenations can also be achieved with 1 at room temperature and without added radical initiators. Simple xanthates are not reduced efficiently in the absence of an initiator, but the reaction proceeds in the presence of AIBN.
Preparation of 1,2- and 1,4-diols via selective cleavage of C-benzotriazole bonds in reductive lithiations of N-(α-alkoxy-benzyl- and -allyl-)benzotriazoles
作者:Alan R. katritzky、Weiliang Bao、Ming Qi、Clara N. Fali、Indra Prakash
DOI:10.1016/s0040-4039(98)01390-2
日期:1998.9
Selective cleavage of C-benzotriazole bonds in the presence of C-O bonds is reported for the reductive lithiation of N-(alpha-alkoxybenzyl)benzotriazoles and N-(alpha-alkoxyallyl)benzotriazoles in a one-step or two-step process. Trapping of the intermediates with carbonyl compounds gave unsymmetrically protected 1,2 or 1,4-diols in moderate yields. (C) 1998 Elsevier Science Ltd. All rights reserved.
Aerobic oxidation of alcohols with air catalyzed by decacarbonyldimanganese
作者:Shan-Shui Meng、Li-Rong Lin、Xiang Luo、Hao-Jun Lv、Jun-Ling Zhao、Albert S. C. Chan
DOI:10.1039/c9gc02446h
日期:——
The oxidation of alcohols to carbonyl compounds using air as the terminal oxidant is highly desirable. As described in previous reports, the abstraction of α-H of the alcohol is the most important step, and it typically requires not only a metal catalyst but also complex ligands, co-catalysts and bases. Herein, we report a practical and efficient method for the oxidation of primary alcohols, secondary
作者:Jingjun Yin、Mark A. Huffman、Karen M. Conrad、Joseph D. Armstrong
DOI:10.1021/jo052121t
日期:2006.1.1
practical synthesis of ephedrine analogues in high yields and enantiopurity was realized by a highly diastereoselective Meerwein−Ponndorf−Verley (MPV) reduction of protected α-amino aromatic ketones using catalytic aluminum isopropoxide. The high anti selectivity resulted from the chelation of the nitrogen anion to the aluminum. In contrast, high syn selectivity was obtained with α-alkoxy ketones and other