Catalytic H/D exchange reactions of olefins with D
2O were developed. Heating a mixture of olefins and D
2O at 100 °C in the presence of 3 mol % of RuHCl(CO)(PPh
3)
3 leads to the isolation of deuterated olefins. The incorporation of deuterium is found at vinyl carbons and the carbons of alkyl chain directly attached to the vinyl group. The catalytic reaction is applicable for both terminal and internal olefins.
In the presence of MHCl(CO)(PPh
3)
3 (M = Ru, Os), the methyl group of α-methyl styrene and the methylene group of 1,3-diphenylpropene undergo H/D exchange reactions with D
2O at a rate slower than that for the vinyl moiety. Detailed mechanistic studies of the H/D exchange reactions were carried out both experimentally and theoretically. It was found that the different rates of the H/D exchange reactions are related to bond rotations about M-C
α and C
α-C
β bonds.
Catalytic H/D exchange reactions of alcohols with D
2O were also developed. With the ruthenium hydrogen transfer catalyst [[(p-cymene)RuCl(NH
2CH
2CH
2O)]
2(μ-H)]Cl (3 mol %), reactions of a variety of alcohols with D
2O at 80 °C in the presence of KOH lead to the isolation of deuterated alcohols with deuterium regioselectively incorporated at the β-carbon position of alcohols.
An efficient and convenient synthetic method for the preparation of monosubstituted cyclopentadienyl ruthenium complexes was developed. Treatment of RuHCl(PPh
3)
3 with fulvenes without sp
3-CH protons at the carbon α to the exocyclic carbon of fulvene produces cleanly mono-substituted cyclopentadienyl ruthenium complexes (η
5-C
5H
4R)RuCl(PPh
3)
2 via hydride transfer to the electrophilic exocyclic carbon of fulvenes. When fulvenes containing sp
3-CH protons at the carbon α to the exocyclic carbon were used, the reactions produce the expected (η
5-C
5H
4R)RuCl(PPh
3)
2 complexes along with minor amounts of vinylcyclopentadienyl ruthenium complexes due to dehydrogenation.
Two synthetic methodologies were developed for the preparation of half-sandwich osmium complexes with the general formula (η
5-cyclopentadienyl)OsCl(PPh
3)
2. The first approach involves the reactions of OsH
3Cl(PPh
3)
3 with cyclopentadienes. Treatment of OsH
3Cl(PPh
3)
3 with CpH (CpH, Cp*H, indene, and C
5Me
4RH (R=H, Et, n-Pr), gives (η
5-cyclopentadienyl)OsCl(PPh
3)
2 via C-H bond oxidative addition of cyclopentadienes followed by reductive elimination of hydrogen. Another method involves the insertion reactions of OsH
3Cl(PPh
3)
3 with fulvenes. Treatment of OsH
3Cl(PPh
3)
3 with fulvene or tetramethylfulvene gives (η
5-C
5R
4R’)OsCl(PPh
3)
2 (R = H; R’ = -CH
2(p-C
6H
4CH
3), -CH
2(p-C
6H
4OCH
3), -CH
2CMe
3, -CHPh
2 and R = Me; R’ = -CH
2(p-C
6H
4CH
3), -CH
2(p-C
6H
4OCH
3), -CH
2(pyrenyl)).
The reactions of Cp*OsCl(PPh
3)
2 with alkynes were studied. Treatment of Cp*OsCl(PPh
3)
2 with terminal alkynes HC≡CR (R = Ph, TMS) produced Cp*OsCl(PPh
3)(=C=CHR) (R = Ph, H). Treatment of Cp*OsCl(PPh
3)
2 with internal alkyne CH
3O
2CC≡CCO
2CH
3 gave Cp*OsCl(PPh
3)(CH
3O
2CC≡CCO
2CH
3). Reaction of Cp*OsCl(PPh
3)
2 with diphenyl propargylic alcohols gave the osmium allenylidene complex Cp*OsCl(PPh
3)(=C=C=CPh
2). Treatment of Cp*OsCl(PPh
3)
2 with alkynols produced expected vinylidene complexes as well as oxacycliccarbene complexes depending on the length of alkyl chain. Treatment of Cp*OsCl(PPh
3)
2 with HC≡CPh and HC≡CC(OH)Ph
2 in the presence of TlOTf gave cationic osmium vinylidene and allenylidene complexes respectively. Treatment of Cp*OsCl(PPh
3)
2 with alkynols in the presence of TlOTf only gave cationic osmium vinylidene complexes [Cp*Os(PPh
3)
2(=C=CH(CH
2)
n-OH)]
+ (n = 1 - 4).
Reaction of fulvene C
5Me
4CH(C
6H
4PPh
2) with [(p-cymene)RuCl
2]
2 produced ruthenium fulvene complex (η
1:η
6-C
5Me
4CH(C
6H
4PPh
2))RuCl
2. The iodide analog (η
1:η
6-C
5Me
4CH(C
6H
4PPh
2))Rul
2 could be prepared from the reaction of (η
1:η
6-C
5Me
4CH(C
6H
4PPh
2))RuCl
2 with NaI. The cationic species [(η
1:η
6-C
5Me
4CH(C
6H
4PPh
2))RuCl(PPh
3)]PF
6 and [(η
1:η
6-C
5Me
4CH(C
6H
4PPh
2))RuCl(MeCN)]PF
6 could be obtained by treatment of (η
1:η
6-C
5Me
4CH(C
6H
4PPh
2))RuCl
2 with PPh
3 and MeCN respectively in the presence of TlPF
6. The catalytic properties of these fulvene complexes for isomerization of allylic alcohols were also studied.
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