Unusual formation of vinyl ether derivatives in the reaction of tributyltin hydride with Fischer carbene complexes anchored on a chalcogen-stabilized iron carbonyl cluster

Treatment of Fe-2(CO)(6){mu-EC(Ph)=C(E')-[C(OEt)=M(CO)(5)]} (1: E, E' = Se; M = Cr. 2: E, E' = Se; M = W. 3: E = S; E' = Te; M = W) with excess Bu3SnH in hexane at 0 degrees C produces enol ether derivatives: (CO)(6)Fe-2{mu-EC(Ph)(H)-C(E')=C(H)(OEt)} ((Z)-4a: E, E' = Se. (E)-4b: E, E' = Se. (Z)-5a: E = S; E' = Te. (E)-5b: E = S; E' = Te). For E, E' = Se, using 1 equiv of Bu3SnH, the alpha-alkoxyallylstannane complex, (CO)(6)Fe-2{mu-Se(Ph)C=C(Se)-C(OEt)(H)SnBu3} (6), was isolated. The molecular structure of (E)-4b was confirmed by X-ray analysis