A series of [C5Me5Rh(CH2CHR)2] complexes (1a
−
e) have been prepared in which the olefin
bears a bulky silyl substituent, R = (a) SiMe3, (b) SiMe2OEt, (c) Si(OiPr)3, (d) SiMe(OSiMe3)2, (e) SiPh2OiPr. The solid-state structure of 1c has been determined by X-ray crystallography. When complex 1a is heated
(50 °C) in deuterated solvents (C6D6, C6D5CD3, C6D5Cl, or (CD3)2CO), deuterium is incorporated into the
olefinic sites. Thermolysis at higher temperatures results in further H/D exchange and deuteration of both the
SiMe3 and C5Me5 groups. Heating 1a in C6D6 with added substrates (aniline, MeOtBu, MeOSiMe3, Cp2Fe,
cyclopentene, or EtOAc) results in deuteration of these substrates via shuttling of deuterium from C6D6 to the
olefinic sites and then into certain sites of the substrates. Thermolysis of 1a in the presence of vinyltrimethylsilane
at higher temperatures results in C−Si bond cleavage and generation of a silacyclopentadiene complex (6)
whose structure was determined by X-ray analysis. Thermolysis of 1c in C6D6 results in facile H/D exchange
and incorporation of deuterium not only into the vinylic positions but also into the methine and methyl groups
of the isopropyl substituents. At 90 °C in the presence of CH2CHSi(OiPr)3 a catalytic transfer hydrogenation
is observed which converts the vinylsilane to the silyl enolate, Et(iPrO)2SiOCMeCH2. A series of catalytic
transfer hydrogenations were carried out in which alkoxysilanes CH2CHSiMe2OR (R = Et, n-Bu, CHMeEt,
C2H4
tBu, C2H4Ph, CHMePh, CHMeCH2Ph) were converted to the corresponding silyl enolates. Catalytic
conversion of the vinylaminosilane CH2CHSiMe2NHC2H4Ph to the silyl enamine EtSiMe2NHC2H2Ph is
also reported.