Alkyl, Alkylidene, and Alkylidyne Complexes of Rhenium

The reaction of Re(C-t-Bu)(cH-t-Bu)(CH2-t-B~)2 with triflic acid, pentafluorophenol, HBFd.OEt2, or [H(OEt2)21+[BArF41(@ = 3,5-C6HdCF3)2) yields complexes of the general formula Re(C-t-Bu)(CHz-t-B~)3x (X = OTf, OCsF5, BF4, B@4) in 60-80% yield. Re(C-tBuXCH2-t-BuhX reacts with coordinating ligands L (L = py, CH&N, CD30D, THF) to form neopentane and Re(C-t-Bu)(CH-t-Bu)(CH2-t-Bu)(L),X ( n = 1-3) . The reaction of Re(C-tBu)(CH-t-Bu)(CHz-t-Bu)(py)2(0Tf) with NaCsH5, NaLoEt (LoE~ = [CpCo(PO(OEt)2)31, or NaHBpz3 in THF yields Re(C-t-Bu)(CH-t-Bu)(CH2-t-Bu)(y5-C5H5), Re(C-t-Bu)(CH-t-Bu)(CH2t-Bu)(LoEt), or Re(C-t-Bu)(CH-t-BuXCHz-t-Bu)(HBpz3), respectively, while the reaction between Re(C-t-Bu)(CH-t-Bu)(CH2-t-Bu)(py)z(OTf) and 1,4,7-trithiacyclononane produces colorless [Re(C-t-Bu)(CH-t-Bu)(CH2-t-Bu)(y3-S3C~H12)l+[OTflin 96% yield. Re(C-t-Bu)(CHt-Bu)(CHz-t-Bu)(L) (L = Cp, LOEJ and [Re(C-t-Bu)(CH-t-Bu)(CHz-t-Bu)(y3-S3CsHreact with triflic acid to form Re(C-t-Bu)(CH-t-Bu)(L)(OTf) or [Re(C-t-Bu)(CH-t-Bu)(OM(y3-S3C6H~2)]+[0Tfl-, respectively. A similar reaction between Re(C-t-Bu)(CH-t-Bu)(CH2-tBu)(LoE~) and [H(OEt2)2lf[BAFJ in ether produces [R~(C-~-B~)(CH-~-BU)(OE~~>(L~E~)I+[BAF~I-. Re(C-t-Bu)(CH-t-Bu)(CHz-t-Bu)(py)z(OM reacts with H2C-CHR (R = OCH2CH3, C6H5) to yield neohexene and Re(C-t-Bu)(CHR)(CH2-t-Bu)(py)n(OM complexes. Re(C-t-Bu)(CH-t-Bu)(CHz-t-Bu)(py)dOTf) reacts with ethylene to form the unstable methylidene complex, Re(Ct-Bu)(CHz)(CHz-t-Bu)(py)z(OM, which can be trapped upon addition of bpy to yield red Re(Ct-Bu)(CH2)(CHs-t-Bu)(bpy)(OM. Re(C-t-Bu)(CH-t-Bu)(CH2-t-Bu)(py)z(OM reacts with excess ethylene to form colorless R~(C-~-BU)[(CH~)~-~-B~I(C~H~)(~~)~(OM in 85% yield. Re C-tBu)(CH-t-Bu)(CHn-t-Bu)(CH3CN)(OTf) metathesizes 100 equiv of cis-2-pentene in less than 5 min, but the catalyst is not long-lived.