No abstract

The trishomocyclopropeny1 cation has been prepared for the first time and is shown to be a remarkably stable, highly charge-delocalized species. The large J 1 3 C -H value associated with the carbons formally carrying the positive charge, the high-field chemical shift of these carbons, and the absence of hydride shift, all are significant and are consistent with the formulation of 1 subject to the limit of the n.m.r. time scale.On a prepare le cation trishornocycloprop~nyle pour la premiere fois et dCmontrC que c'est une espece d'une stabilite remarquable et oh la charge est hautement delocalisee. Le fait que la valeur de J , 3 c -H soit grande pour les carbones portant la charge positive, de m&mk que le grand deplacernent chirnique vers les champs ClevCs de ces carbones, ainsi que ]'absence d e transfert d'hydrure sont tous significatifs et en accord avec la formulation de 1 dans les limites de I'CcheIle de temps de la r.m.n.[Traduit par le journal]Can. J. Chem., 52,855 (1974)

SunzmaryThe charge-delocalized cation (1) has been IN view of the interest1s2 shown in the recent experimental work on the (CH) 2 specie^,^ we record the preparation of the cation (l), structurally related to cation (2).3asbA reasonable precursor for cation (1) is compound (3). The reported synthesis4 o f (3) is multi-step and of low generated from two precursors which have been prepared via unique double bond participation of a cyclopropyl cation in solvolysis.

and 3,4,5,6-tetrahydro-7-methoxy-2H-azepine ( I b ) undergo a mild exothermic reaction with aziridines (Z), yielding 1 -iminomethyl-substituted aziridines (3) ( Table I).

The 13C n.m.r. spectruin of the cation 4 suggests the presence of considerable 1.7-bonding. indicating that it should be described as a substituted homotropylium cation rather than a monocyclic lor-electron system. The intra-annular ca-rbon atoms of 3 and 4 do not show a significant upfield shift due to the ring current. Explanations are offered. [Traduit par le journaljOur recent demonstration that both cis-and tive to changes in the geometry of the molecule trans-[l Olannulenes (1 and 2) are non-planar (5); we have used bicyclo [5.4.1 ldodecapentaolefinic hydrocarbons (1) contrasts with the be-2,5,7,9,11-ene (5) (6)