Triangulanes: stereoisomerism and general method of synthesis

The class of spirocondensed cyclopropanes, triangulanes, is defined and stereochemical problems of unbranched triangulanes (UTs) are considered from an algebraic-combinatorial point of view. The general method of triangulane synthesis that consists of the addition of chloromethylcarbene to methylenecyclopropanes with subsequent dehydrochlorination and final cyclopropanation of the resulting methylenetriangulanes is suggested and realized for [5]- and [6]-members of the family