Heteroatom-facilitated ortho carbon-carbon bond formation in nucleophilic F-phenyl substitution
作者:Takaaki Sonoda、Yoshinari Inukai、Hiroshi Kobayashi
DOI:10.1016/s0022-1139(00)84053-1
日期:1980.12
pentanediol, respectively. Treating 1a or 1b with either Grignard reagents (CH3MgI, C2H5MgBr, nC3H7MgBr) or organolithium reagents (CH3Li, nC4H9Li) gave appreciable yields of the 2-substituted F-phenyloxazoline (2a) or F- phenyldihydrooxazine (2b), while no 4-substituted ones were identified. The use of an excess of the organometallic reagents afforded 2,6-disubstitution in preference to 2,4-disubstitution
通过转化为F-苯基恶唑啉(1a)或F-苯基二氢恶嗪(1b),然后在非极性溶剂中用有机金属试剂亲核取代一种或两种邻氟来实现F-苯基羧酸及其衍生物的区域选择性邻位取代。分别通过用2-氨基-2-甲基-1-丙醇处理F-苯甲酰氯和用2-甲基-2,4-戊二醇处理F-苄腈可以轻松地制备必需品1a和1b。治疗1a或1b与任一格氏试剂(CH 3 MGI,C 2 ħ 5 MgBr,nC 3 ħ 7 MgBr)或有机锂试剂(CH 3栗,nC 4 ħ 9Li)给出了2-取代的F-苯基恶唑啉(2a)或F-苯基二氢恶嗪(2b)的明显产率,而未鉴定出4-取代的。使用过量的有机金属试剂优先于2,4-二取代提供2,6-二取代。可以想象,这里观察到的正交效应是通过类似于Meyers(Tetrahedron Lett。,223(1978))所提出的机制引起的。