Organomercurials in the synthesis of triquinane-type molecules

The synthesis and application of organomercurials as intermediates is discussed. Readily available organomercurial 2013 can be used as a versatile starting material for the construction of a variety of triquinane-type molecules. Thus cupration, followed by oxidation of the resulting alcohol gave the corresponding cylclobutanone,42 whose treatment with vinylmagnesium bromide afforded 86. The latter product can easily rearrange to afford 90, 102 or 103; the regioselectivity is controlled by the reagent/catalyst employed.;Reduction of 20 (using a novel protection-deprotection technique) furnished alcohol 65, which was then converted into six-membered lactone 114, via palladium(II) catalysed carbonylation.112 Alcohol 65 was also used to afford tetrahydrofuran derivative 66, upon treatment with bromine.;The synthetic utility of organomercurial 20 has been extended further by using a reductive demercuration process. This protocol has facilitated synthesis of diol 79, which could then be selectively oxidised to subsequently afford lactone 110. Treatment of bromomercurial 20 with methyl copper gave a methylmercurial derivative,43 which could then be added to Tebbe reagent to furnish organomercurcial 76. Subsequent oxidation of 76 using the reductive demercuration technique, produced an alcohol that could be converted, over several steps, to provide a route to enone 115. (Fig. 8699).;.