Synthese und reaktionen von (CO) 5Mo[C(Aryl)H

Abstract

The pentacarbonyl(α-ethoxybenzyl)molybdates NEt 4 {(CO) 5Mo[C(OEt)(C 6H 4R- p)H]} react with HBF 4·Et 2O by abstraction of the ethoxy group to give the benzylidene complexes (CO) 5Mo[C(C 6H 4R- p)H] (R = Me ( 2a), OMe ( 2b)). The compounds 2 are thermally very labile and react rapidly even at −100°C with a number of nucleophiles. The addition of PPh 3 to the benzylidene carbon atom of 2a gives the ylide complex (CO) 5Mo[C(PPh 3)(C 6H 4Me- p)H] and that of PPh 2Cl gives the phosphine complex (CO) 5MoP[C(Cl)(C 6H 4Me- p)H]Ph 2 under rearrangement. The reaction of 2b with PPhCl 2 stereoselectively gives RS/SR-(CO) 5Mo{P(Ph)(Cl)-[C(Cl)(C 6H 4OMe- p)H]} and with [XCN] − (X = S, Se) gives the heterobenzaldehyde complexes (CO) 5Mo[XC(C 6H 4Me- p)H] (X = S ( 6b), Se ( 7b). The thioacrylamide complex (CO) 5Mo[SC(NEt 2)C(Me)C(C 6H 4OMe- p)H] is obtained from the reaction of 6b with MeCCNEt 2. The [4 + 2]-cycloaddition of 7b with cyclopentadiene gives a (CO) 5Mo-coordinated selenanorbornene derivative. Cyclopropanation is observed in the reaction of 2b with cyclopentadiene. The resulting bicyclo[3.1.0]hexene which is coordinated to (CO) 5Mo via the CC bond can be cleaved off the metal by air.