Benzocyclohepten 6,7,8,9-tetrahydro

Substrate 16 reacts under irradiation in DMSO with the enolate anions of 1-indanone (n= 1), 1-tetralone (n = 2), and 6,7,8,9-tetrahydro-benzocyclohepten-5-one (n = 3) to afford fused indoles (Sch. 21) [92]. 

Photocyclisation of 8-alkoxy-l,2,3,4-tetrahydro-l-naphthalenones and 4-alkoxy-6,7,8,9-tetrahydro-5H-benzocyclohepten-5-ones gives naphtho[l, 8-bc]furans and cyclohepta[cd]benzofurans respectively, and conformational and substituent effects of 1,5-biradicals in the cyclisation process are discussed." " The same authors also describe substituent effects on the photocyclisation of ethyl 2-(8-oxo-5,6,7,8-tetrahydro-l-naphthyloxy)acetates and ethyl 2-(5-oxo-6,7,8,9-tet-rahydro-5H-benzocyclohepten-4-yloxy)acetates to give naphtho[l,8-bc]furans and cyclohepta[c,d]benzofurans respectively." Also reported are cyclisations involving photogenerated radical cations of unsaturated silyl enol ethers, fragmentation cyclisations of unsaturated ot-cyclopropyl ketones which occur by photoelectron transfer and give polycyclics, and kinetic and theoretical studies of [2+3] cycloadditions of nitrile ylids. These reactions have been studied mechanistically and their synthetic potential investigated. 

Hingegen photoisomerisiert 3-Methyl-l-phenyl-4,5-dihydro-phosphol zu 1-Phenyl-3-methylen-2,3,4,5-tetrahydro-phospol (36-54% d.T.h)7. 7H-Benzocyclohepten geht in geringer Ausbeute in 5H-Benzoeyclohepten (

[Pg.215]

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