On treatment with n-butyllithium, 4-alkoxy- and 4-silyloxy-2-(tributylstannylmethoxymethyl)-1,6-dimethyl-1-(phenylsulfonylmethyl)cyclohex-2-enes undergo tin-lithium exchange followed by [2,3]-Wittig rearrangements to give 3-alkoxy- and 3-silyloxy-2-hydroxymethyl-5,6-dimethyl-1-methylene-6-(phenylsulfonylmethyl)cyclohexanes in which the 2-hydroxymethyl and 6-phenylsulfonylmethyl residues are cis-disposed about the six-membered ring. In contrast, the corresponding 1-(phenylsulfanylmethyl)cyclohexenes give mainly methylenecyclohexanes with the 2-hydroxymethyl and 6-phenylsulfanylmethyl groups trans-disposed about the six-membered ring. This stereoselectivity is independent of the nature of the alkoxy- or silyloxy-substituent and configuration at C4. The 3-tert-butyldiphenylsilyloxy-1-methylene-6-(phenylsulfonylmethyl)cyclohexane was converted into a macrocyclic precursor of the phomactins.
- Natural products
- Total synthesis
- [2,3]-Wittig rearrangements
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Blackburn, T. (Creator), Helliwell, M. (Creator), Kilner, M. (Creator), Lee, A. T. L. (Creator) & Thomas, E. (Creator), Cambridge Crystallographic Data Centre, 4 Dec 2008
Blackburn, T. J. (Creator), Kilner, M. J. (Creator) & Thomas, E. (Creator), Cambridge Crystallographic Data Centre, 21 Jan 2015