Conjugated dienes hydrogenolysis

Epoxide opening with nucleophiles occurs at the less substituted carbon atom of the oxlrane ting. Cataiytic hydrogenolysis yields the more substituted alcohol. The scheme below contains also an example for trons-dibromination of a C—C double bond followed by dehy-drobromination with strong base for overall conversion into a conjugated diene. The bicycKc tetraene then isomerizes spontaneously to the aromatic l,6-oxido[l0]annulene (E. Vogel, 1964). 

The enone 807 is converted into the dienol triflatc 808 and then the conjugated diene 809 by the hydrogenolysis with tributylammonium for-mate[689,690]. Naphthol can be converted into naphthalene by the hydrogenolysis of its triflate 810[691-693] or sulfonates using dppp or dppf as a ligand[694]. Aryl tetrazoyl ether 811 is cleaved with formic acid using Pd on carbon as a catalyst[695]. 

---