An Approach toward the Triquinane-Type Skeleton via Reagent-Controlled Skeletal Rearrangements. A Facile Method for Protection−Deprotection of Organomercurials, Tuning the Selectivity of Wagner−Meerwein Migrations, and a New Route to Annulated Lactones
rearrangement (3 --> 8), (2) an intramolecularorganometallicaddition across a C=O bond triggered by activation of the C-HgX group by means of Me(3)CuLi(2) (14 --> 26), and (3) selective, reagent-controlled skeletal rearrangements (43 --> 47 with Tl(3+) or Hg(2+); 43 --> 51 + 52 with Pd(2+); 44 --> 47 with Pd(2+)). A new method for protection/deprotection of organomercurials has been developed, which allows
Corner opening of cyclopropanes by mercury(II) and thallium(III) and transmetalation of the intermediate organomercurials. A novel, stereoselective approach to cyclobutanes and cyclopropanes
compared, and further evidence for the exclusive corner selectivity for Hg2+ is provided by isotope labeling. Cleavage of cyclopropyl derivative 1 with Hg(NO3)2, followed by KBr quenching, afforded the stable, rearranged organomercurial 3, whose transmetalation has been studied. Whereas reaction of 3 with Pd(I1) afforded lactol 4, treatment with MezCuLi resulted in the formation of cyclobutanol derivative