Formation of 3-halobenzyne: solvent effects and cycloaddition adducts.
Noncoordinating solvents permit the halogen-metal exchange-induced formation of benzyne (aryne) from di- and trihalobenzene precursors in the presence of cyclopentadiene to give 1,4-dihydro-1,4-methano-naphthalenes. Studies with mixed halide precursors and nonacidic Diels-Alder diene traps reveal that ethereal and hydrocarbon solvents influence the halide leaving group facility, resulting in a reversal of 3-halobenzyne regioselectivity.
Coe
Jotham W
JW
Pfizer Global Research and Development, Groton Laboratories, Pfizer, Inc, Groton, Connecticut 06340, USA. coejw@groton.pfizer.com
Wirtz
Michael C
MC
Bashore
Crystal G
CG
Candler
John
J