A diastereoselective synthesis 1-trimethylsilyl-(E)-1,3-alkenynes and a simple synthesis of alkyl trimethylsilylethynyl ketones via organoboranes

被引:2
作者
Bhat, NG [1 ]
Wawroski, P [1 ]
Perez-Garcia, G [1 ]
Elizondo, M [1 ]
机构
[1] Univ Texas Pan Amer, Dept Chem, Edinburg, TX 78541 USA
关键词
organoboranes; diastereoselective;
D O I
10.1016/j.tetlet.2005.05.134
中图分类号
O62 [有机化学];
学科分类号
070303 ; 081704 ;
摘要
A convenient, novel diastereoselective synthesis of 1-trimethylsilyl-(E)-1,3-alkenynesand a convenient synthesis of alkyl trimethylsilylethynyl ketones based on Z-1-bromo-1-alkenyl boron ate esters are developed. alpha-Bromo-(Z)-1-alkenylboronate esters readily available using literature procedures smoothly undergo a reaction with trimethylsilylethynyllithium (derived from the deprotonation of trimethylsilylethyne with n-butyllithium) in tetrahydrofuran to provide the corresponding 'ate' complexes. These 'ate' complexes undergo intramolecular nucleophilic substitution reactions to afford the corresponding (E)-1-alkenylboronate esters containing trimethylsilylethynyl moiety which upon protonolysis with acetic acid provide the corresponding 1-trimethylsilyl-(E)-1,3-alkenynes in good yields (70-82%) and in high stereochemical purities (> 98%). These intermediates upon oxidation with hydrogen peroxide and sodium acetate afford the corresponding alkyl trimethylsilylethynyl ketones in good yields (66-78%). (c) 2005 Elsevier Ltd. All rights reserved.
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页码:5153 / 5155
页数:3
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