PREPARATION AND REACTIONS OF SOME (TRIMETHYLSILYL)CYCLOPROPENES - SYNTHESIS OF IN OUT TRICYCLIC [N.3.2.0/2,4] COMPOUNDS, POTENTIAL PRECURSORS TO CYCLOPROPAPARACYCLOPHANES

l,2-Bis(trimethylsilyl)cyclopropene (7), l,2,3-tris(trimethylsilyl)cyclopropene (11), and 3,3-dibromo-l,2-bis-(trimethylsilyl)cyclopropene (13a) were prepared from l,2-bis(trimethylsilyl)acetylene (6) by the addition of the appropriate carbene. l-Bromo-2-(trimethylsilyl)cyclopropene (5b) and 3,3-dimethyl-l-(trimethylsilyl)cyclopropene (17) were prepared by modification of previous routes from tribromocyclopropanes. 2,2’-Bis(trimethylsilyl)-bicyclopropenyl (20) and 3,3,3',3'-tetramethyl-2,2'-bis(trimethylsilyl)bicyclopropenyl (22) were prepared by metalation of the appropriate halocyclopropene, but Diels-Alder addition to these bicyclopropenyls did not give the desired adducts. Diels-Alder addition of 13a to (E,Z)-cyclododeca-l,3-diene (27a) gave the tricyclic in-out adduct 28 and addition of 1,2-dibromocyclopropene (4) to 27a and to (E,Z)-cycloundeca- 1,3-diene (27b) gave the corresponding tricyclic in-out adducts 29a and 29b. © 1990, American Chemical Society. All rights reserved.