PtCl2-Promoted cyclopropane opening in [4+2+2] homo Diels–Alder cycloadducts

A new and readily available catalytic system has been developed to open the cyclopropane ring in [4+2+2] homo Diels–Alder cycloadducts formed by reaction of norbornadienes and 1,3-butadiene. The cobalt-mediated homo Diels–Alder reaction followed by this PtCl2-promoted isomerization is a key step in the efficient route to bicyclo[5.3.0]decanes, core of numerous natural products.