Cycloisomerization of alkynols at transition metal templates

The metal-assisted cycloisomerization of omega-alkynols to oxacycloalkylide ne complexes is reviewed. A variety of low-valent coordinatively unsaturate d transition metal templates from group 6 to 10 mediate the cyclization of omega-butynols, -pentynols, and -hexynols to give the corresponding oxacycl oalkylidene cycloalkylidene complexes is reviewed. A variety of low-valent complexes. In some cases kinetic hydroxyalkylvinylidene coordinatively unsa turated transition metal templates from complex intermediates can be isolat ed and characterized.