Michael G. Matturro

Bicyclo[2.2.0]hex-1(4)-ene

Abstract The preparation of bicyclo [2.2.0]hex- 1(4)-ene ( 1 ) via ring expansion of a cyclopropylcarbene or the dehalogenation of 1-bromo-4-chlorobicyclo[2.2.0]hexane is described. It is one of the most reactive of the alkenes which may be observed at room temperature. Its reactions, including dimerization and cycloaddition reactions, are described. The latter lead to convenient preparations of [m.2.2]propellanes. The vibrational spectrum was examined via matrix isolation and ab initia MO calculations.

Geometrical inversion of methoxymethyl cations

The barrier for geometrical isomerization of the title ion [ΔH‡= 11·9 kcal mol–1, ΔS‡=–4 cal mol–1 K–1(1 cal = 4·184 J), variable temperature n.m.r. spectrum 270 MHz] agrees with ab initio(4-31G) calculations for an inversion process (ΔEcalc= 12·0 kcal mol–1); the values computed for a rotation around the C+–O bond (20·8 kcal mol–1) or at the STO-3G level (25·2 and 32·8 kcal mol–1, respectively) are too high.

X-Ray crystal structure of 1,5-dibromotetracyclo[4.2.2.2.2,502,6]dodecane

The reaction of tricyclo[4.2.2.22,5]dodeca-1,5-diene with bromine gives a novel saturated dibromide with a 1,5-bridge, as determined by X-ray crystallography.