INTRAMOLECULAR COOPERATIVE REACTIONS OF 1,2-BIS(DIAZOKETONE)S - THE FIRST SYNTHESES OF TRANS-HYDRO-1H-2-INDEN-1-ONES

The intramolecular cooperative reactions of 1,2-bis(diazoketone)s init iated by the Wolff rearrangement of alpha-diazoketones have been inves tigated. Under thermal conditions, 1,2-bis(diazoketone)s are efficient ly transformed into 2-cyclopenten-1-one derivatives with complete ster eospecificity. Thus, a most extraordinary result is reported, that tra ns-hydro-2-inden-1-ones (1-3) were synthesized for the first time from trans-1,2-bis(diazoketone)s (5, 11, and 12), respectively. The unprec edented trans-hydroindenone structure was confirmed by X-ray analysis of 3 as well as H-1 NMR analysis and was supported by ab initio molecu lar orbital calculations. The same reactions were also carried out und er photochemical conditions and were applied to 1,3-bis(diazoketone)s, giving 2-cyclohexen-1-one derivatives.