Reactions of Alkyl Halides with Silver Nitrate in Pyridine¹

Trans Dialkoxylation of Cyclic Alkenes: A Prévost-Type Reaction

“…Initial formation of cyclohexene iodiranium ion followed by anti-mode nucleophilic attack by either tetrafluoroborate (with transfer of fluoride ion), 5 or by MeOH provides the iodofluoride 1 and intermediate iodoether 2. The paths for methanolysis of iodoether 2 to the diether 3a and acetal 4 are based on results of studies on Ag + -assisted solvolyses of alkyl halides by Pocker and Kevill and coworkers, 6, 7 Vona and Steigman, 8 and others. 7 Such reactions appear to occur via alkyl halide-silver salt complexes, followed by iodide abstraction by silver ion to give ion-paired species, which then undergo either nucleophilic displacement by S N 2Ag-type processes, or dissociate to free carbocations, followed by nucleophile trapping via S N 1Ag-type processes; the latter being favored by more electrophilic silver salts such as perchlor-ate or tetrafluoroborate, weak nucleophiles, and by strong acids and polar solvents.…”

Stereochemistry and Mechanism in Reactions of Silver Salts with Alkyl Halides. The Reaction of Silver Nitrite with Alkyl Halides1,2

“…Here, in contrast to the 2-octyl system, the stereochemical course of the reac- " All rotations are observed rotations of the pure liquid in a 1-dm tube at temperatures in the range 25-28°. 6 See ref 10. tion depends on the solvent. Treatment of optically active -phenylethyl chloride in ethyl ether solution with silver nitrite gives the nitro compound and nitrite ester of the same configuration as the chloride.12 However, when the reaction is conducted in cyclohexane the -phenylethyl nitrite and a-phenylnitroethane are of the inverted configuration relative to the chloride.…”

“…All rotations are observed rotations of the pure liquid in a 1-dm tube at temperatures in the range 25-32°. 6 See ref 10. = We are indebted to Dr. W. D. Gurowitz for this experiment.…”