Unexpected formation of the first doubly benzylic 1,1-di-Grignard reagent

Citation
Hjr. De Boer et al., Unexpected formation of the first doubly benzylic 1,1-di-Grignard reagent, MAIN GR MET, 24(2), 2001, pp. 93-98
Citations number
31
Categorie Soggetti
Chemistry
Journal title
MAIN GROUP METAL CHEMISTRY
ISSN journal
07921241 → ACNP
Volume
24
Issue
2
Year of publication
2001
Pages
93 - 98
Database
ISI
SICI code
0792-1241(2001)24:2<93:UFOTFD>2.0.ZU;2-2
Abstract
Reaction of 1-bromo-2-(1-chloro-1-trimethylsilylmethyl)benzene (3) with mag nesium in THF expectedly gave the corresponding 1,3-di-Grignard reagent 1b in 44 % yield, but in addition, the isomeric 1,1-di-Grignard reagent 4 was obtained in equal amounts. Compound 4 is remarkable for two reasons: it is one of the few examples of a 1,1-di-Grignard reagent, and its formation inv olves rearrangement by 1,3-migration of a trimethylsilyl group which provid es further evidence for the occurrence of carbanionic intermediates such as 11 during the formation reaction of Grignard reagents.