Metathetical reactions of rhenium(VII) alkylidene-alkylidyne complexes of the type Re(CR')(CHR')[OCMe(CF3)2]2 (R' = CMe3 or CMe2Ph) with terminal and internal olefins

Abstract

1-Decene and methyl 9-decenoate react with syn- and anti-Re(C-t-Bu)(CH-t-Bu)(OR[sub F6]) to give syn- and anti-Re(C-t-Bu)[CH(CH[sub 2])[sub 7]Me](OR[sub F6])[sub 2] and syn- and anti-Re(C-t-Bu)[CH(CH[sub 2])[sub 7]CO[sub 2]Me](OR[sub F6])[sub 2], respectively (OR[sub F6] = OCMe(CF[sub 3])[sub 2]). The new alkylidene complexes are unstable in the presence of excess terminal olefin and decompose upon attempted isolation. However, vinylferrocene reacts relatively smoothly and reversibly with syn-Re(C-t-Bu)(CH-t-Bu)(OR[sub F6])[sub 2] in a noncoordinating solvent to yield tert-butylethylene and primarily anti-Re(C-t-Bu)(CHFc)(OR[sub F6])[sub 2] (Fe = ferrocenyl). anti-Re(C-t-Bu)(CHFc)(OR[sub F6])[sub 2]. In the presence of THF or dimethoxyethane, complexes of the type syn- or anti-Re(C-t-Bu)(CHR)(OR[sub F6])S[sub 2] (R = Me, Et, Ph; S = THF or 0.5DME) could be prepared in high yield from Re(C-t-Bu)(CH-t-Bu)(OR[sub F6])[sub 2] and CH[sub 2][double bond]CHR. Heteroatom-substituted (O, S, or N) terminal olefins react more rapidly than ordinary olefins with Re(C-t-Bu)(CH-t-Bu)(OR[sub F6])[sub 2] in the presence of THF to yield complexes of the type syn- or anti-Re(C-t-Bu)(CHX)(OR[sub F6])[sub 2](THF)[sub 2] (X = OR, SR, NR[sub 2], or p-dimethylaminophenyl). 2-Pentene or methyl oleate is metathesized in the presence of Re(C-t-Bu)(CH-t-Bu)(OR[sub F6])[sub 2], and intermediate alkylidene complexes can be observed in each case. Addition of 3-hexene to Re(C-t-Bu)(CH-t-Bu)(OR[sub F6])[sub 2] followed by TMEDA yields Re(C-t-Bu)(CHEt)(OR[sub F6])[submore » 2](TMEDA). Internal olefins are metathesized only very slowly by Re(C-t-Bu)(CH-t-Bu)(OR[sub F6])[sub 2] in the presence of several equivalents of THF or DME or especially in neat THF or DME. 58 refs., 4 figs., 4 tabs.« less