Bicyclohepta-2,5-dienes

Tetrasubstituted thiirans (324 R = H, R = H, Me, Bu, C02Et, or Ph) and (324 R = R = Me) (74—100%) have been synthesized by the reaction of pyrazolinethione (323) with the corresponding diazo-compound R R CN2. Elemental sulphur has been found to react with polycyclic alkenes to give 1,2,3-trithiolans, but in the particular reaction of sulphur with bicyclohepta-2,5-diene the e co-sulphide (325) (10%) has been obtained for the first time. ... 

For example, 3-perfluoroalkyl-4-ethoxycarbonylfuranes 48 have been prepared from bicyclohepta-2,5-diene derivatives 49 by sequence involving cycloaddition of acetylene to tetracyclone 50 and retro Diels-Alder reaction of the cycloadduct. ... 

Nishida, M. Hayakawa, Y. Matsui, M. Shibata, K. Muramatsu, H. Synthesis and photochemical reaction of l,4-dialkyl-7-oxa-2,3,5,6-tetrakis(trifluoromethyl) bicyclohepta-2,5-diene. J. Heterocycl. Chem. 1992, 29, 113-116. 

The first hving polymerization of cyclic olefins with a high ring strain [28], such as norbomenes, norbornadienes (bicyclohepta-2,5-dienes, NBDs) or the Feast-monomer 7,8-bis(trifluoromethyl)tricyclo[4.2.2.0 ]deca-3,7,9-triene (TCDTFj) by W(N-2,6 i Pr2 C6H3)(CH- Bu)(OCMe(CF3)2) [34] was re-... 

Phenyl-l,2,4-triazoline-3,5-dione acts as a dienophile by in situ reaction with butadiene, cyclopentadiene, cycloheptatriene, and bicyclohepta-diene (62TL615). Thus, it is possible to compare the reactivity of the cis-azo dienophile (110) with trans-azo dienophiles, such as ethyl azodicar-boxylate, which has been observed to undergo alternate modes of reaction when used with less reactive or hindered dienes. Treatment of (110) with several dienes resulted in exclusively Diels-Alder addition. The results are summarized in Table III. 

Transition metal-catalyzed carbenoid insertion into the k system of aryl compounds followed by ring expansion of the resultant [4.1.0]bicyclohepta-2,4-diene provides the... 

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