ISSN:
0009-2940
Keywords:
Homo Diels-Alder reactions
;
Cyclopropanetetracarbonitrile derivatives
;
Barbaralane derivatives /Urazoles, polycyclic /6-Thiatricyclo[3.2.1.02.7]oct-3-ene 6,6-dioxide
;
Chemistry
;
Inorganic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Reactions of Homobenzvalenes with 4-Phenyl-3H-1,2,4-triazole-3,5(4H)-dione, Tetracyanoethylene. Chlorosulfonyl Isocyanate, and Sulfur Dioxide. Several Concerted 1,4-Additions to a Vinylcyclopropane SubunitHomobenzvalene (le) and its derivatives 1f.g with an anellated four-membered ring reacted with 4-phenyl-3H-l,2,4-tri- azole3,5(4H)-dione (PTAD) to give the pentacyclic urazole 2e and its hexacyclic derivatives 2f, g, respectively. Tetracyano- ethylene (TCNE) and le in benzene afforded only the Diels- Alder adduct 5 of norcaradiene. In other solvents the homo Diels-Alder adduct 3a of le was formed as the main product together with some 5 and a small fraction of the cyclohexa- dienylcyclopropanetetracarbonitrile 4a. 5-Methylhomobenz- valene (lh) and TCNE in acetonitrile gave 3b and 4b in the ratio 10: 1. On treatment with TCNE, dihydrohomobenzvalene (6) was converted into 8, which is structurally related to 4. In contrast, tetracyc10[4.1.0.02,4.03,5]]heptane (7) and TCNE gave rise to the tetracyclic adduct 9 and a minor quantity of 5. Chlorosulfonyl isocyanate reacted with le to furnish mainly the N-(chlorosulfony1)imino ether 10 and the N-(chlorosulfonyl)-lactams 11 and 12a as well as a further isomer as byproducts. On heating, 10 rearranged to 12a. The Ksulfonyl chlorides 10, 11, and 12a were transformed to the N-unsubstituted compounds 16,15, and l7, respectively, by treatment with sodium sulfite/aqueous potassium hydroxide. In wet [D6]dimethyl- sulfoxide 10 was converted into a cycloheptatriene derivative (14) as well as the rearranged and hydrolyzed lactam 15, whereas 11 gave 15 exclusively. Exposure of le to sulfur dioxide yielded the 1,4 adduct 18 to the vinylcyclopropane subunit of le. Possible mechanisms of the reactions of the homobenzvalenes are discussed. In particular, the pathways to 3, 18, and at least to a fraction of 10 and 11 are considered to be concerted six-electron processes. - The structures of 4a and 10 have been established by X-ray analyses.
Additional Material:
2 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/cber.19901230537
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