The formation of C-H insertion products in the course of direct photolysis of α,α-diphenylsubstituted diazo ketones of the tetrahydrofuran series was rationalized by secondary photochemical processes which give rise to benzophenone acting as a sensitizer. Triplet excited states of diazo ketones generated by the action of benzophenone are capable of undergoing bimolecular transformations.Singlet excited states generated by direct irradiation of diazo carbonyl compounds are capable of undergoing only very fast unimolecular transformations. Among the latter, the most typical is Wolff rearrangement which involves elimination of nitrogen molecule and leads to the formation of ketenes and carboxylic acid derivatives [1]. This reaction is especially effective with cyclic and heterocyclic diazo ketones, and the yields of 1,2-nucleophilic rearrangement (ring contraction) products reach 80-90% and more [1].On the other hand, bimolecular processes were also observed with some diazo ketones of the tetrahydrofuran series. For example, we previously [2] described bimolecular photochemical transformation of 4-diazo-2,2,5,5-tetraphenyltetrahydrofuran-3-one which reacted with the solvent (tetrahydrofuran) to produce the corresponding substituted hydrazone, i.e., the process was accompanied by elimination of nitrogen. It should be specially emphasized that the described reaction was the first example of photochemical transformation of diazo ketones without elimination of nitrogen.Insofar as we failed to effect similar transformation of tetraalkyl-substituted analogs [3], we presumed that the presence of phenyl substituents in the α-positions with respect to the diazo and/or carbonyl group in the initial diazo ketone is crucial. Presumably, α-phenyl groups are responsible for the formation of long-lived triplet states from diazo ketones.Thus the goal of the present work was to study the above previously unknown photochemical reaction [4] using as substrates regioisomeric α,α-diphenyl-substituted diazo ketones Ia and Ib belonging to the tetrahydrofuran series [5]. Initially, analysis of the reaction mixtures showed that the main path of photochemical transformations of both diazo ketones Ia and Ib is the Wolff rearrangement (to 73%) leading to the formation

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Cycloalkane C 10 H 18 Formation During Skeleton Isomerization of endo-1,7,7-Trimethyl-2-chloro-bicyclo[2,2,1]heptane by AlCl 3 . -The reaction of title chlorobicycloheptane (I) with AlCl3 (trichloroethylene, 20°C) proceeds with skeletal rearrangement to furnish a mixture of isomeric cycloalkanes with the molecular formula C10H18, C11H20, C20H28 or higher. The C10H18 isomers are identified as compounds (II) -(V). -(VISHNYAKOVA, E. V.; UTSAL', V. A.; VATLINA, L. P.; PONOMAREV, D. A.; Izv. Vyssh. Uchebn. Zaved., Khim. Khim. Tekhnol. 46 (2003) 8, 148-149; St. Peterburgskaya lesotekh. akad., St. Petersburg, Russia; Russ.) -Mischke 28-092

Reaction of Perfluoroiodoalkanes with Trimethylstannylalkoxyacetylenes. -Treatment of the title compounds (I) and (V) with (II) leads to a mixture of isomeric adducts such as (III)/(IV) or (VI)/(VII). Acidolysis of the latter and (IV) gives the olefins (VIII)/(IX) and (X) , whereas thermolysis of (III) yields the corresponding perfluoroacetylene via Me3SnI-elimination. -(KUVALDIN, K. V.; KLYUCHINSKII, S. A.; ZAVGORODNII, V. S.; UTSAL', V. A.; LIEPIN'SH, Z. Z.; PETROV, A. A.; Zh. Obshch. Khim. 64 (1994) 1, 77-80; S.-Peterburgskii tekhnol. univ., St. Petersburg, Russia; RU)

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