A rapid entry into the dynemicin core structure: remarkable solvent effect on an η2-hexacarbonyldicobalt propargylic cation cyclization

Abstract

3-(tert-Butyldimethylsilyloxy)quinoline 8 on treatment with the diynene 9 gave the diynene 10(64%), and deprotection of 10 gave 11(88%) which was converted into the η²-Co₂(CO)₆ adduct 12; treatment of 12 with (CF₃SO₂)₂O in CH₂Cl₂–MeNO₂ at –10°C gave the cyclized product 13(43%), and decomplexation of 13 using I₂–THF produced the stable azabicyclo[7.3.1]tridecadiynene core structure 7 of the antitumour antibiotic dynemicin 1.