results in the formation of the corresponding silyl enolethers or β-ketosilanes. The relative ratio of these products varies with the ylide conditions and the stability of ylide used. It is noteworthy that silyl enolethers were formed under the salt-free ylide conditions, and that β-ketosilanes were yielded in the presence of soluble inorganic salts in THF, selectively. The formation of both products
REACTION OF 1-TRIMETHYLSILYLCYCLOPROPYLLITHIUM DERIVATIVES WITH DICHLORO-METHYL METHYL ETHER. A NOVEL SYNTHESIS OF CYCLOPROPYL SILYL KETONES
作者:Tadashi Nakajima、Masaru Tanabe、Katsuhiko Ohno、Masahito Segi、Sohei Suga
DOI:10.1246/cl.1986.177
日期:1986.2.5
Treatment of 1-trimethylsilylcyclopropyllithium derivatives with dichloromethyl methyl ether affords the corresponding newcyclopropylsilylketones in moderate yield. This reaction involves the intramolecular 1,2-silicon shift from carbon to carbon.
Treatment of cyclopropyl silyl ketones with trimethylsilyl trifluoromethanesulfonate as a strong acid having low nucleophilic counter anion gives the corresponding 5-silyl-2,3-dihydrofuran derivatives, exclusively, regardless of substituents on the cyclopropane ring or silicon atom. The resulting 5-silyl-2,3-dihydrofuran derivatives exhibit both reactivities of the vinylsilane and the cyclic enolether in the
Reaction of cyclopropylacylsilanes with sulfuric or triflic acid in aprotic solvent affords the corresponding cyclobutanone or 2-silyl-4,5-dihydrofuran derivatives, depending upon the substituents on the three-membered ring or acid used. The use of triflic acid results in the selective formation of the dihydrofurans.