Catalytic removal of tert-butyldimethylsilyl (TBS) ether by PVP-I
摘要:
A mild, efficient and rapid protocol the deprotection of alcoholic TBDMS ethers using PVP-1 as catalyst in methanol, the procedure of deprotection of various TBDMS ethers were found to be very convenient, easy work-up, high yielding. (C) 2019 Elsevier Ltd. All rights reserved.
Acid-Catalyzed Cyclization of Vinylsilanes Bearing a Hydroxy Group: A New Method for Stereoselective Synthesis of Disubstituted Tetrahydrofurans<sup>1</sup>
with a dimethylphenylsilyl group, and (E)-vinylsilanes show much lower reactivity than the corresponding (Z)-isomers. The cyclization proceeds by stereospecific syn addition of the hydroxy group. Vinylsilanes 17, 19, and 21, (Z)-5-silyl-4-penten-1-ols bearing a substituent on the methylene tether, smoothly undergo the acid-catalyzed cyclization to give trans-2,5-, cis-2,4-, and trans-2,3-disubstituted
Copper-Catalyzed Cross-Coupling of Nonactivated Secondary Alkyl Halides and Tosylates with Secondary Alkyl Grignard Reagents
作者:Chu-Ting Yang、Zhen-Qi Zhang、Jun Liang、Jing-Hui Liu、Xiao-Yu Lu、Huan-Huan Chen、Lei Liu
DOI:10.1021/ja304848n
日期:2012.7.11
Practical catalytic cross-coupling of secondary alkyl electrophiles with secondary alkyl nucleophiles under Cu catalysis has been realized. The use of TMEDA and LiOMe is critical for the success of the reaction. This cross-coupling reaction occurs via an S(N)2 mechanism with inversion of configuration and therefore provides a general approach for the stereocontrolled formation of C-C bonds between
已经实现了在铜催化下仲烷基亲电试剂与仲烷基亲核试剂的实际催化交叉偶联。TMEDA 和 LiOMe 的使用对于反应的成功至关重要。这种交叉偶联反应通过构型反转的 S(N)2 机制发生,因此为手性仲醇的两个叔碳之间立体控制形成 CC 键提供了通用方法。
Stereoselective Synthesis of <i>cis</i>-2,5-Disubstituted THFs: Application to Adjacent Bis-THF Cores of Annonaceous Acetogenins
intermediates. N-Iodosuccinimide (NIS) effectively worked as an activator of the double bonds in the substrates and the silyl enol ether. Application to an expedient synthesis of the adjacent bis-tetrahydrofuran core of Annonaceousacetogenins with a cis/threo/cis relative stereochemistry is also described.
Cobalt-Catalyzed Stereoselective Synthesis of 2,5-<i>trans</i>-THF Nitrile Derivatives as a Platform for Diversification: Development and Mechanistic Studies
作者:Sajjad Ali、Henrique Milanezi、Tânia M. F. Alves、Cláudio Francisco Tormena、Marco A. B. Ferreira
DOI:10.1021/acs.joc.8b00575
日期:2018.8.3
straightforward protocol integrating a sustainable approach for the synthesis of new 2,5-trans-THF nitrile derivatives enabling an easy diversification of its side chain scaffolds is described. The reaction tolerated different aromatic and alkyl substituents, affording the corresponding 2,5-trans-THFs in high diastereoselectivity. A detailed mechanisticstudy using DFT calculation reveals details of the ligand-exchange