A NOVEL SYNTHETIC APPROACH TO CYCLOOCTA-1,5-DIYNES AND CYCLOOCT-3-ENE-1,5-DIYNES VIA COBALT-COMPLEXED PROPARGYL RADICALS

摘要

A novel synthetic strategy has been elaborated to produce Co-2(CO)(6)-complexed 1,5-cyclooctadiynes and the first cyclooct-3-ene-1,5-diyne derivative. Eight-membered rings are formed with high dl-diastereoselectivity (de greater than or equal to 98%) by reduction of the corresponding propargyl dication complexes under hetero- (Zn) and homogeneous (Na/Ph(2)CO) conditions. A novel ''red-ox'' decomplexation method has been developed for 1,5-cyclooctadiynes. [References: 40]