40677-59-6Relevant academic research and scientific papers
Photochemistry of phosphate esters: An efficient method for the generation of electrophiles
Givens, Richard S.,Matuszewski, Bogdan,Athey, Phillip S.,Robert Stoner
, p. 6016 - 6021 (2007/10/02)
The photochemical cleavage of benzyl diethyl phosphates, 1a-g, has been examined in tert-butyl alcohol, which produces the corresponding benzyl tert-butyl ether as the major solvolysis product upon direct irradiation. The multiplicity of the reactive excited state has been established as the singlet state. Evidence favoring an intermediate benzyl cation-phosphate ion pair formed from photofragmentation includes oxygen-18 scrambling, racemization of chiral benzyl phosphates, and substituent effects on the rate of reaction. The existence of an electrophilic intermediate is further supported by a linear free energy relationship for the rate of disappearance of 1, kdis, with Hammett σ, which gave a ρ value of -0.90 and for the rate of appearance of 2, kapp, a Hammett ρ value of -0.97. Possible mechanisms including an electron transfer either before or after homolysis or simple heterolysis of the ester bond are evaluated.
Generation of Bicycloheptatrienes
Billups, W. E.,Reed, Larry E.,Casserly, Edward W.,Lin, L. P.
, p. 1326 - 1333 (2007/10/02)
Derivatives of bicycloheptatriene have been generated in solution by the base-induced dehydrochlorination of gem-dichlorocyclopropanes.Reaction of 7,7-dichlorodibenzobicycloheptane with potassium tert-butoxide in tetrahydrofuran at 0 deg C gives mainly products derived from solvent incorporation by carbene insertion.Evidence that the carbene results from rearrangement of the bicycloheptatriene derives from the successful interception of the bicycloheptatriene with nucleophile (MeS-). endo-7-Chlorodibenzobicycloheptane failed to reactwith potassium tert-butoxide in tetrahydrofuran.Generation of benzobicycloheptatrienes was also accomplished via the base-induced dehydrochlorination of gem-dichlorocyclopropanes. 1-Methylbenzobicycloheptatriene gives products derived from multiple carbene-carbene rearrangements.In contrast, nonannelated methylbicycloheptatrienes generated by the dehydrochlorination route give only carbene-derived products resulting from the initially produced bicycloheptatriene.
