Acceleration of alkyne metathesis in multicomponent catalytic systems by use of alternative Mo(0) sources under optimised conditions

Abstract. Alkyne metathesis in multicomponent catalytic systems, although subject to changes, is still a domain of molybdenum hexacarbonyl as a source of Mo(0). Our findings show that this coordination compound is relatively inert under metathesis conditions, which results in noticeably long induction of catalytic activity, and the kinetics of this transformation can greatly benefit from switching to more labile Mo(0) complexes. Several easily obtainable ones had been tested and [Mo(CO)3(py)3] has been chosen as the one exhibiting the most desired features, i.e. nearly instant catalytic activity and relative stability in the air

In situ Mo(CO)₆-based catalysts for alkyne metathesis: Silanols vs phenols as co-catalysts under thermal and photochemical activation

International audienceA systematic study on the use of silanols and phenols as effective activators in Mo(CO)₆-based catalytic systems for metathesis of 4-decyne and 1-phenyl-1-propyne is reported. In comparison with traditionally used phenols, aryl-substituted silanols exhibit high activating potential of molybdenum species even at lower concentrations (2 mol% of Mo(CO)₆ and 4-20 mol% of silanol depending on the alkyne) at toluene reflux. Silylated phenols and silanols are also suitable as co-catalysts. Additionally, Mo(CO)₆/silanol catalytic system is shown to be efficiently activated by UV-irradiation at room temperature, whereas it is less effective for metathesis reactions performed in the presence of phenols