Bicyclo [2.1.1] hexane. Preparation and Photochlorination

A simple method for the preparation of bicyclo[2.1.1]hexane, which is based on the mercury (3P1) sensitized isomerization of 1,5-hexadiene, is described. Photochlorination of bicyclo[2.1.1]hexane in the gas phase, in solution in carbon tetrachloride or trifluorotrichloroethane, or as pure liquid, led to more than 95% of a single monochloride in good yield. Evidence to show that this compound is 2-chlorobicyclo[2.1.1]hexane is presented. Further chlorination gave 2,2-dichlorobicyclo[2.1.1]hexane and trans-2,3-dichlorobicyclo[2.1.1]hexane as products. © 1967, American Chemical Society. All rights reserved.