Reactions of 1,1-dihaloalkenes with triorganozincates: a novel method for the preparation of alkenylzinc species associated with carbon-carbon bond formation
作者:Toshiro Harada、Takeshi Katsuhira、Daiji Hara、Yasuo Kotani、Keiji Maejima、Ryousuke Kaji、Akira Oku
DOI:10.1021/jo00070a027
日期:1993.8
Lithium trialkylzincates react with 1,1-dibromoalkenes 1 and 1-bromo-1-chloroalkenes 2 at -85-degrees-C in THF to give 1-bromoalkenes 5 and 1-chloroalkenes 7, respectively, upon hydrolysis. The intermediate (1-haloalkenyl)zincates 4 and 6 are stable at low temperature but, when allowed to warm to 0-degrees-C, they undergo a 1,2-alkyl migration reaction to afford alkenylzinc species 10. A variety of alkylation products 11 are obtained by the hydrolysis of 10. In the presence of (Ph3P)2Pd (5 mol%), alkenylzinc species 10 react smoothly with organic halides (AcCl, EtOCOCl, CH2=CH-(Me)Br, PhBr) to yield the corresponding coupling products 13-16.