Reactions of bicyclobutylidene and 1,3-bis(trimethylene)propadiene : Synthesis of trispiro[3.0.3.0.2.0]undecane, 9-methylenedispiro[3.0.3.1]nonane,and bicyclobutylidene-2,2'- and 2,4'-dione

A number of reactions of bicyclobutylidene (1) and 1,3-bis(trimethylene)propadiene (2), directed towards the preparation of compounds in which conjugated and steric effects of the cyclobutane ring could be evaluated, are described. Trispiro3.0.3.0.2.0] undecane (4) was prepared from 1, and 1-cyclobutylidenespiro3.2]hexane (8b) from 2. Thermolysis of 8b gave 9-methylenedispiro3.0.3.1]nonane (14). Oxidation of 1 with singlet oxygen gave the “ene” product 17, and an attempted two step conversion to the dioxetane via the bromohydroperoxide 19 also gave 17. Oxidation of 2 with peroxyacids gave products which probably arose from either the allene oxide or the bis-oxirane. The cyclobutane ring does not appear to afford any steric protection to allow the isolation of the dioxetane or allene oxide. Three unsucessful routes directed towards the synthesis of bicyclobutenyl (24) are described, and the syntheses of bicyclobutylidene-2,4'-dione (39) and -2,2'-dione (40) are reported.