Tandem cycloalkanes

Scott and coworkers [60] have also investigated applications of AM to cycloalkanes. They found, for example, that cyclooctane undergoes metathesis by 7 in tandem with 1, 4a, or 6, to give a range of cyclic products, including (surprisingly) cycloheptane, but mostly low cyclooligomers in which the carbon number is a multiple of 8. The proposed mechanism is shown in Scheme 3. 

More recently, the same principle was applied by the same authors to cyclic alkanes for catalytic ring expansion, contraction and metathesis-polymerization (Scheme 13.24) [44]. By using the tandem dehydrogenation-olefin metathesis system shown in Scheme 13.23, it was possible to achieve a metathesis-cyclooligomerization of COA and cyclodecane (CDA). This afforded cycloalkanes with different carbon numbers, predominantly multiples of the substrate carbon number the major products were dimers, with successively smaller proportions of higher cyclo-oligomers and polymers. 

The reaction tolerated various functional groups, thus allowing the in situ preparation of allylboron compounds possessing a carbonyl group (Equation (32)).236 The tandem diboration-intramolecular allylboration provided a diastereoselective access to the cycloalkanes bearing 1,3-diols. 

Intramolecular substitutions involving an allylsilane moiety as well as following a metallo-ene reaction pattern have been reported. Tandem metallo-ene cyclization and vinylstannane coupling serve to construct cycloalkanes with vicinal alkenyl chains. " ... 

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