Frédéric Gohier, Anne‐Sophie Castanet, J. Mortier
May 29, 2003
Citations
0
Influential Citations
31
Citations
Journal
Organic letters
Abstract
[reaction: see text] Exposing 2-fluorobenzoic acid (1a) to 2.2 equiv of LTMP at ca. -78 degrees C leads to deprotonation at the 3-position whereas 2-chloro/bromobenzoic acids (1b,c) are lithiated adjacent to the carboxylate. The resulting dianions 3Li-1a and 6Li-1b,c are trapped as such by chlorotrimethylsilane. In the absence of internal quench, 6Li-1b,c isomerize to the more stable 3Li-1b,c. The latter eliminate lithium halide and set free benzyne-3-carboxylate (2) that reacts regioselectively with LTMP to give 3-tetramethylpiperidinobenzoic acid (3).