Photochemically Driven Tandem Process in the Construction of a Biscyclopropylcage from 2,5-Dimethoxy-p-benzoquinone and Terminal Acetylenes.

A photochemical two-step one-pot synthesis of novel biscyclopropyl-box-shaped compounds via the reaction of 2,5-dimethoxy-para-benzoquinone and monosubstituted alkynes is reported. The reaction mechanism for a process in which six new C-C bonds are formed is explored by means of experimental and computational techniques. The whole process occurs with complete selectivity, and only one densely decorated diastereomer is obtained; such a degree of control and substitution makes for a rather powerful and complexity-building process.