Chemoselective protection of thiols versus alcohols and phenols. The Tosvinyl group

被引:28
作者
Arjona, O [1 ]
Medel, R
Rojas, J
Costa, AM
Vilarrasa, J
机构
[1] Univ Barcelona, Fac Quim, Dept Quim Organ, E-08028 Barcelona, Catalonia, Spain
[2] Univ Complutense, Fac Quim, Dept Quim Organ 1, E-28040 Madrid, Spain
关键词
addition reactions to triple bonds; thiol protecting group; 1-(ethynylsulfonyl)-4-methylbenzene (tosylacetylene);
D O I
10.1016/S0040-4039(03)01614-9
中图分类号
O62 [有机化学];
学科分类号
070303 ; 081704 ;
摘要
The conjugate addition of aliphatic and aromatic thiols to ethynyl p-tolyl sulphone (tosylacetylene) has been managed to afford Tosvinyl derivatives chemo selectively (in the presence of oxygen nucleophiles) and stereo selectively (isomers Z) in practically quantitative yields. The conditions of choice are: catalytic amounts of Et3N (only 0.5-1.0 mol%), a reaction temperature around 0degreesC and, for the less acidic thiols, CF3CH2OH or CH3CN/CF3CH,OH as the solvent. Thus, N-Boc-Cys-OMe has been quantitatively protected as its S-Tosvinyl derivative in the presence of N-Boc-Ser-OMe and N-Boc-Tyr-OMe. This novel protecting group is stable to several basic and acidic conditions; its removal is achieved at rt by treatment with an excess of pyrrolidine or at 0degreesC with alkanethiolate ions. (C) 2003 Elsevier Ltd. All rights reserved.
引用
收藏
页码:6369 / 6373
页数:5
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