Chiral Fluorinated α-Sulfonyl Carbanions: Enantioselective Synthesis and Electrophilic Capture, Racemization Dynamics, and Structure
作者:Gunther Hellmann、Achim Hack、Eric Thiemermann、Olaf Luche、Gerhard Raabe、Hans-Joachim Gais
DOI:10.1002/chem.201204014
日期:2013.3.18
Enantiomerically pure triflones R1CH(R2)SO2CF3 have been synthesized starting from the corresponding chiral alcohols via thiols and trifluoromethylsulfanes. Key steps of the syntheses of the sulfanes are the photochemical trifluoromethylation of the thiols with CF3Hal (Hal=halide) or substitution of alkoxyphosphinediamines with CF3SSCF3. The deprotonation of RCH(Me)SO2CF3 (R=CH2Ph, iHex) with nBuLi
对映体纯的三氟甲酮R 1 CH(R 2)SO 2 CF 3已从相应的手性醇经硫醇和三氟甲基硫烷开始合成。硫烷合成的关键步骤是用CF 3 Hal(Hal =卤化物)对硫醇进行光化学三氟甲基化或用CF 3 SSCF 3取代烷氧基膦二胺。RCH的去质子化(Me)的SO 2 CF 3(R = CH 2 PH,我十六进制)与Ñ丁基锂与形成盐的[RC(Me)中 SO 2 CF 3Li和它们的亲电捕获都具有高对映选择性。所述SO的位移2 CF 3基团(的小号)-MeOCH 2 C(Me)的(CH 2 PH)SO 2 CF 3(95% EE)由乙基通过与ALET反应3得到烷烃MeOCH 2 C(我)(CH 2 Ph)Et的96% ee。盐的外消旋[R 1 C(R 2)SO 2 CF 3[Li]遵循一级动力学,主要是一个焓过程,负极化熵和动态NMR(DNMR)光谱表明该负激活熵较小。这是根据与C α