DIACETOXYLATION OF CONJUGATED DIENES WITH THALLIUM(III) ACETATE IN ACETIC ACID

Article abstract of DOI:10.1016/S0040-4020(01)92012-5

The reaction of conjugated dienes such as 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 2,5-dimethyl-2,4-hexadiene, 1,3-cyclopentadiene, and 1,3-cyclohexadiene with thallium(III) acetate in acetic acid at 10-65 deg C for 0.5-15 hr affords an isomeric mixture of the corresponding diacetoxyalkenes (1,2- and 1,4-addition products) in 10-92 percent yields.The 1,2-addition products are predominantly formed in all cases examined except the case of 1,3-cyclopentadiene.The reaction is assumed to proceed through acetoxythallation and dethallation steps, the latter step being accompanied and/or followed by an attack of acetoxyl group.An initial attack of thallium moiety is proposed to occur mainly at C-1 and C-2 carbons in the cases of linear terminal dienes and cyclic dienes, respectively.