Protonation of rhenium 1,3-enyne and 1,3-diyne complexes: formation of exo-alkylidene η3-allyl and η3-propargyl complexes
摘要:
Protonation of eta(2)-enyne rhenium complex C5Me5(CO)(2)Re(eta(2)-3,4-trans-PhCdropCCH=CHPh) (24) occurred at the coordinated alkyne to produce 1-metallacyclopropene complex C5Me5(CO)(2)Re[eta(2)-trans-(PhHC=CH)CCHPh]+BF4- (26), instead of protonation at the non-coordinated alkene to produce an eta(3)-propargyl complex. Protonation of the alkene coordinated eta(2)-enyne rhenium complex C5Me5(CO)(2)Re(eta(2)-1,2-cis-PhHC=CHCdropCPh] (25) occurred at the non-coordinated alkyne to produce exo-alkylidene eta(3)-allyl complex C5Me5(CO)(2)Re(eta(3)-exo,anti-CHPhCHC=CHPh)+BF4- (27), instead of protonation at the coordinated alkene to produce an eta(3)-propargyl complex. Protonation of eta(2)-diyne complex C5Me5(CO)(2)Re(eta(2)-CH(3)CdropCCdropCCH(3)) (32) at 78 C produced the rhenium hydride complex trans-C5Me5(CO)(2)ReH(eta(2)-CH(3)CdropCCdropCCH(3))+BF4- (33), which was converted to exo-alkylidene eta(3)-propargyl complexes C5Me5(CO)(2)Re[eta(3)-(CH3CH=)CCdropCCH(3)]+BF4- (34a and 34b) at 0 degreesC. (C) 2002 Elsevier Science B.V. All rights reserved.