Reactions of Cyclopropyl Chlorides with Metals and Lithium Naphthalene Radical Anion and Dianion

Article abstract of DOI:10.1021/jo01304a010

The reaction of exo- and endo-anti-3-chlorotricyclo<3.2.1.0^2,4>oct-6-ene with magnesium in THF followed by deuterolysis gave syn/anti deuteration ratios of 2.2 and 0.42, respectively, with 85percent monodeuterium incorporation.Analysis of the exo hydrocarbon involved epoxidation followed by a shift-reagent study with Eu(fod)3.Reaction of the same halides with Na/t-BuOD gave 95percent deuterium incorporation with syn/anti ratios of 1.2 and 0.37, respectively.Similarly, reaction of anti-3-chloro-exo-tricyclo<3.2.1.0^2,4>octane with Na, K, and Li in t-BuOD/THF gave 95percent deuterium incorporation with syn/anti ratios of 2.11, 1.25, and 1.70.No effect of temperature or solvent composition was observed in the potassium reduction.Reaction of this halide with Li in Et2O followed by D2O gave 87percent deuterium incorporation with a syn/anti ratio of 2.1, while reaction with lithium naphthalene in THF at -78 deg C followed by addition of D2O gave 96percent deuterium incorporation with a syn/anti ratio > 100.All of the above results are described in terms of radical equilibria and competing electron transfers.Reaction of anti-3-bromo-exo-tricyclo<3.2.1.0^2,4>octane with butyllithium in ether at 0 deg C followed by deuterolysis gave entirely anti deuteration (anti/syn ratio > 16) with 95percent deuterium incorporation.Reaction of anti-3-chloro-exo-tricyclo<3.2.1.0^2,4>octane with lithium naphthalene dianion proceeded at -78 deg C in THF with a rate constant of 5.5 x 10^-2 M^-1 min ^-1, while under identical conditions lithium naphthalene exhibited a rate constant of 1.0 M^-1 min^-1.Deuterolysis of the dianion solution gave a syn to anti deuterium incorporation ratio greater than 50.