Studies in the Cycloproparene Series: Formation of a New Dimer of 1H-Cyclopropa[b]naphthalene

Abstract

1-(Trimethylsilyl)-1H-cyclopropa[b]naphthalene (10) and its 1-methyl derivative (11) have been isolated as pure compounds from use of a lipophilic size exclusion gel. Acylation of the 1H-cyclopropa[b]naphthalenyl anion (2) is effected with N,N -dimethyl-benzamide and -acetamide to give (5) and (6), respectively. Analogous reactions with the 1-(trimethylsilyl)-1H-cyclopropa[b]naphthalenyl anion (9) do not yield the 1-acyl-1-(trimethylsilyl)-1H-cyclopropa[b]naphthalenes (12) and (13); instead the novel 6-methyl- 7H-dibenzo[b,g]fluorene (15) results from attempted acetylation. Compound (15), a formal dimer of 1H-cyclopropa[b]naphthalene (1), is formed also from anion (9) both in toluene and from addition of hydrocarbon (1); its structure is assigned from spectroscopic data and confirmed by single-crystal X-ray analysis.