Cs2CO3 promoted O-alkylation of alcohols for the preparation of mixed alkyl carbonates
作者:Feixia Chu、Eric E. Dueno、Kyung Woon Jung
DOI:10.1016/s0040-4039(99)00084-2
日期:1999.3
The presence of cesium carbonate and tetrabutylammonium iodide (TBAI) facilitated efficient O-alkylation of alcohols with alkyl halides, giving rise to the exclusive formation of mixed alkyl carbonates. The cesium effect was also examined comparatively with other alkali carbonates. (C) 1999 Elsevier Science Ltd. All rights reserved.
Cesium promoted O-alkylation of alcohols for the efficient ether synthesis
作者:Eric E. Dueno、Feixia Chu、Seok-In Kim、Kyung Woon Jung
DOI:10.1016/s0040-4039(99)00083-0
日期:1999.3
Efficient Williamson type O-alkylation of alcohols was developed using cesium bases in the presence of tetrabutylammonium iodide (TBAI) and molecular sieves. Various substrates including unreactive primary and secondary alcohols were converted smoothly to the corresponding ethers. Electrophiles used herein encompass primary bromides and reactive halides such as benzyl bromide and MPMCl. (C) 1999 Elsevier Science Ltd. All rights reserved.
Cesium Hydroxide Promoted Chemoselective <i>N</i>-Alkylation for the Generally Efficient Synthesis of Secondary Amines
作者:Ralph N. Salvatore、Advait S. Nagle、Shaun E. Schmidt、Kyung Woon Jung
DOI:10.1021/ol9910417
日期:1999.12.1
[GRAPHICS]Selective N-alkylation of primary amines was developed using cesium hydroxide to prepare various secondary amines efficiently. A cesium base not only promoted monoalkylations of primary amines but also suppressed overalkylations. Various amines and alkyl bromides were examined, and the preliminary results demonstrated this methodology was highly chemoselective, favoring mono-N-alkylation over dialkylation. In particular, use of amino acid derivatives afforded the desired secondary amines exclusively.
Reduction of carboxylic esters to ethers with triethyl silane in the combined use of titanium tetrachloride and trimethylsilyl trifluoromethanesulfonate
作者:Michihisa Yato、Koichi Homma、Akihiko Ishida
DOI:10.1016/s0040-4020(01)00420-3
日期:2001.6
Aliphatic acyclic and cyclic ethers are prepared on treatment of their corresponding carboxylic esters and lactones with triethylsilane in the presence of titanium tetrachloride and trimethylsilyl trifluoromethanesulfonate. (C) 2001 Elsevier Science Ltd. All rights reserved.