Pt- and Au-catalyzed oxidative cyclization of 2-ethenyl-1-(prop-2'-yn-1'-ol)benzenes to naphthyl aldehydes and ketones: catalytic oxidation of metal-alkylidene intermediates using H2O and H2O2.

2-Ethenyl-1-(prop-2'-yn-1'-ol)benzenes was cyclized through catalytic oxidation with PtCl(2)/CO/H(2)O and PEt(3)AuCl/H(2)O(2); the metal-naphthylidene intermediates were identified and oxygenated with water and H(2)O(2), respectively; for the efficiency of cyclization, the Au catalytic system is superior to that of the PtCl(2)-catalysis because of its compatibility toward diverse alcohol substrates including both internal alkynes and terminal alkynes.

Platinum-catalyzed aromatization of enediynes via a C-H bond insertion of tethered alkanes.

PtCl2 (5 mol%) is an effective catalyst for aromatization of enediynes via a C-H bond insertion of tethered alkanes. The reaction mechanism of this cyclization is proposed to involve platinum-pi-alkyne intermediates. This cyclization works not only for terminal alkynes but also for internal alkynes.