29748-93-4Relevant academic research and scientific papers
Vinyl Cations. 41. Influence of 4-Aryl and 4-Alkyl Substituents on the ?-Route Solvolyses of Homopropargyl Esters
Collins, Clair J.,Hanack, Michael,Stutz, Herbert,Auchter, Gerhard,Schoberth, Winfried
, p. 5260 - 5268 (2007/10/02)
The four 4-substituted-homopropargyl tosylates and triflates 6b-e (R=phenyl, p-tolyl, anisyl, and cyclopropyl) have been synthesized and solvolyzed under various conditions, as have 2-cyclopropyl-1-cyclobutenyl triflate (11-OTf) and nonaflate (11-ONf).In addition, the solvolyses of pent-3-yn-1-yl tosylate (6a-OTs, R=methyl) and triflate (prepared previously) are reported.The ratios of C-3 ring to C-4 ring 3 ring/C4ring)> products are recorded for the reactions in various solvents.As expected, ring closure (kΔ) increases and solvent displacement (kS, SN2) decreases with decreasing nucleophilicity of solvent.Temperature effects are noted for the sovolyses of tosylates 6a-e in 100percent TFE buffered with Na2CO3 in which kΔ increases with increasing temperature.The result is explained by decomposition of the intimate ion pair with temperature, whereupon elimination to the enyne becomes smaller and ring closure (kΔ) increases at the expense of elimination.The possibility of intervention of nonclassical vinyl cations is discussed, as are other mechanistic implications.
