Diphenylmethylidenecyclobuta[a]cyclopropa[d]benzene:  Synthesis and Spectral Characterization

Abstract

[reaction: see text] The first derivative of the novel and highly strained rocketene (cyclobuta[a]cyclopropa[d]benzene) 5, namely, the C4 diphenyl-substituted exocyclic alkene 8, has been prepared in 16% overall yield as a yellow oil with properties fully consistent with its highly strained nature.

Cycloproparenes

“…By changing the leaving groups on 141 to the silyl ether (R 1 ) and tributylstannyl (R 2 ) of 141c , McNicholls and Stang 131 were able to effect the ring closure in 65% yield, thus making 28 readily available. The reaction sequence provides 141c from 1,5-diyne and yne by analogy to the Vollhardt synthesis, but it must be noted carefully that the experimental details provided by the authors omit the critical requirement of irradiation (from a projector bulb close to the reaction vessel) in order to obtain 141c . This success in providing the highly strained 28 argues forcefully for comparable o, α-eliminations to provide other cycloproparene derivatives.…”

“…The reaction sequence provides 141c from 1,5-diyne and yne by analogy to the Vollhardt synthesis, but it must be noted carefully that the experimental details provided by the authors omit the critical requirement of irradiation (from a projector bulb close to the reaction vessel) in order to obtain 141c. 133 This success in providing the highly strained 28 argues forcefully for comparable o,R-eliminations to provide other cycloproparene derivatives.…”

Combining Aromaticity and Strain with Tetsuo Nozoe—A Passage of Time with Friends

“…It served to remind me of Nozoe's life‐long fascination with the seven‐membered ring and the tropolones in particular. Apart from the properties of all these compounds being duly assessed, extensions eventually took us to the cyclobutacyclopa derivative rocketene 22 , and the propadienone 23 that has transient existence even at low temperatures . As I noted above, Tetsuo Nozoe's interest was evident from his questions—as astute and adept as always and showing little effect of the passage of four years since first meeting him (Figure ).…”

Conjugated and Cross‐Conjugated π‐Extended Cycloproparenes with Dithiole and Cyclopentadiene Functionality

“…2 ) in routine syntheses to give exocyclic alkenes (e.g. 5 ) from Peterson olefinations (Scheme ) 5−8. Because of the notable malodour of volatile 1 , the bulk of the studies have employed crystalline cyclopropa[ b ]naphthalene 6 to provide a wide range of examples1 (e.g.…”