摘要:
Reductive cyclization of aryl and vinyl iodides tethered to vinylogous acyl trifiates (VATS) induces a ring-expanding fragmentation to provide cyclic alkynyl ketones, including strained nine-membered cycloalkynes, in fair to excellent yield. The tandem cyclization/C-C bond-cleavage is Initiated under carefully optimized conditions by halogen metal exchange in the presence of carbonyl and vinyl triflate functionality. A modified protocol for alkylation of 1,3-cyclohexanedione is described for preparing the relevant VAT substrates.