Directed ortho metalation methodology. The N,N-dialkyl aryl O-sulfamate as a new directed metalation group and cross-coupling partner for Grignard reagents.
[reaction: see text] The ortho metalation (RLi/THF/-93 degrees C) of 3 followed by quench with a variety of electrophiles constitutes a new general route to substituted aryl O-sulfamates 4a-k. The Kumada-Corriu cross-coupling of O-sulfamates 4e, 4n-s, and 6a with Grignard reagents gives biaryls 9a-m, and the use of 2-halo and boron derivatives 4h, 4i, and 4k for Suzuki-Miyaura cross-coupling and generation of benzynes leads to naphthols 7a and 7b. A relative metalation ranking of the OSONEt(2) is reported.
Macklin
Todd K
TK
Department of Chemistry, Queen's University, Kingston, ON, K7L 3N6, Canada.
Snieckus
Victor
V