Five-carbon scrambling

One of the most striking differences between Winstein s and our work is the fact that the bicyclo[3.2.0] cations, reported in this chapter, are observable61. Although the [2.2.1] isomers have been observed in some cases, the thermodynamically more stable ions always turned out to have the [3.2.0] skeleton. The difference is nicely demonstrated in the five-carbon scrambling process. Winstein assumed a [3.2.0] cation 55 to be involved as an intermediate in the scrambling of the observed ion 37l3, (see also Scheme 11), whereas we assume that a [2.2.1 ] cation 56-d3 is an intermediate in the scrambling of the observed [3.2.0] carbon 51-d3 (Scheme 38). The position of the equilibrium is not dependent on the presence of the C=C double... 

The photochemistry of indene and several alkylindenes in solution and in the gas phase, using deuterated substrates, however, reveals extensive intramolecular scrambling of hydrogen and carbon in the five-menibered ring by multiple hydrogen and alkyl migrations27. 

Five papers detail the chemistry of tricobalt alkylidyne complexes of the type [ 03(00)9(113-CR)] " . These include the preparation of [Mo2( l-02CR )4] (R = 03(00)9(113-0)) , and a study of the redox properties of compounds containing two of these cluster units linked via various carbon fragments. The scrambling of carbonyls between [0o2(0O)J and [Oo((X))4] is proposed to occur through an intermediate tricobalt complex [Oo3(CX))io], and not via ion... 

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