Cyclopropyl solvolyses. III. Parent cyclopropyl derivatives and methyl-substituted cyclopropyl tosylates

Abstract

Acetolysis results for the various (3-methyl-substituted cyclopropyl tosylates are reported. The kinetic results are correlated with a treatment based on electronic and steric effects in ground and transition states, assuming stereospecific ring opening according to the Woodward-Hoffmann-DePuy predictions and considerable progress toward allyl cations in the transition states. The results of the standard mechanistic criteria [m value, (kRa ai J £ « ) , k0TjkBr, and a-methyl/hydrogen rate ratio] for the parent cyclopropyl system indicate that solvolysis is a concerted process. The magnitude of anchimeric assistance in the cyclopropyl system is estimated by two

Cyclobutane—Physical Properties and Theoretical Studies

“…Despite its low reactivity, it is important to note that it is considerably more reactive than 7-norbornyl tosylate that has a 94 • C−C−C bond angle 35 . It appears that the solvolysis of cyclopropyl tosylate is assisted by the development of allyl cation character in the transition state 36 . Cyclobutyl tosylate (4) would be expected to have reduced reactivity because it, again, will suffer an increase in strain on going to a carbocation due to the constrained C−C−C bond angles.…”

Palladium(II)-Catalyzed Olefin Addition Polymerizations of 3,3-Dialkyl-Substituted Cyclopropenes

“…A considerable number of Pd(II) compounds can be used for the synthesis of strictly alternating copolymers of α-olefins and carbon monoxide. − Furthermore, Pd(II) and Ni(II) catalysts can promote the olefin addition polymerization of strained bicyclic olefins (eq 1). , The bicyclic structure of the monomer remains intact, and polymers with rigid structures are obtained. The driving force for these latter reactions is based on the release of ring strain and the energy gained from converting a π-bond into a σ-bond. , Cyclic monomers previously used include norbornene, norbornadiene, 7-oxanorbornadiene, and their derivatives 7 and also polycylic olefins such as dicyclopentadiene, 7e,n benzonorbornadiene,7e and endo,exo -1,4;5,8-dimethano-1,2,3,4,4a,5,8,8a-octahydronaphthalene 7e …”

Charge Development and Mechanism in Disrotatory Ring Opening of Cyclopropyl Bromides

“…Solvolytic studies of cyclopropyl derivatives have attracted attention for many years (1)(2)(3)(4)(5)(6)(7)(8).…”