Abstract: Compounds of the formula:M(NR.sup.1)(OR.sup.2).sub.2 (CHR.sup.3)whereinM is molybdenum or tungsten;R.sup.1 and R.sup.2 are alkyl, aryl, aralkyl or halogen-substituted derivatives or silicon-containing analogs thereof;R.sup.3 is an alkyl, aryl, aralkyl or any substituent that results from the initial reaction between the M.dbd.CHR.sup.3 complex and the olefin(s) that is(are) being metathesized; alkyl has 1-20 carbons, aryl has 6-20 carbons and aralkyl h as 7-20 carbons.These compounds are catalysts for the metathesis of ordinary olefins (hydrocarbons) and especially functionalized olefins in the homogeneous phase.