Fluorine??Flanked Congested Sites: Minimal, Though Perceptible Buttressing Effects on the Proton Mobility of Arenes

C Heiss, F Leroux, M Schlosser

Index: Heiss, Christophe; Leroux, Frederic; Schlosser, Manfred European Journal of Organic Chemistry, 2005 , # 24 p. 5242 - 5247

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Citation Number: 10

Abstract

Abstract (2, 6-Difluorophenyl) trimethylsilane,-triethylsilane and-triisopropylsilane undergo sec-butyllithium-mediated metalation at the 3-and 4-position (ortho and meta relative to the halogen) in ratios of 99.6: 0.4, 98: 2 and 95: 5, respectively. The steric pressure transmitted by the fluorine atoms can be increased if the trialkylsilyl group is locked up on the other side by a relatively voluminous substituent. Whereas (2, 6-difluorophenyl) triethylsilane is ...