A novel synthetic route to poly(β‐ketone)s via poly(alkoxyethyne)s

Isopropoxyethyne (1a) and tert ‐butoxyethyne (1b) were polymerized using group 5 and 6 transition metal catalysts to give poly(isopropoxyethyne) (2a) and poly( tert ‐butoxyethyne) (2b) , respectively. The weight‐average molecular weight ( M̄ w ) of the resulting poly(alkoxyethyne)s was up to 1.0 × 10 4 . Among the transition metal catalysts, a tungsten alkoxide or a molybdenum alkoxide having low Lewis acidity were found to effectively promote the polymerization without causing side reactions. Poly( tert ‐butoxyethyne) was successfully converted to poly(β‐ketone) 3 by acid hydrolysis of the tert ‐butyl vinyl moiety.