52389-13-6Relevant academic research and scientific papers
Demystifying Cp2Ti(H)Cl and Its Enigmatic Role in the Reactions of Epoxides with Cp2TiCl
Gordon, Jonathan,Hildebrandt, Sven,Dewese, Kendra R.,Klare, Sven,Gans?uer, Andreas,Rajanbabu,Nugent, William A.
supporting information, p. 4801 - 4809 (2019/01/08)
The role of Cp2Ti(H)Cl in the reactions of Cp2TiCl with trisubstituted epoxides has been investigated in a combined experimental and computational study. Although Cp2Ti(H)Cl has generally been regarded as a robust species, its decomposition to Cp2TiCl and molecular hydrogen was found to be exothermic (ΔG = -11 kcal/mol when the effects of THF solvation are considered). In laboratory studies, Cp2Ti(H)Cl was generated using the reaction of 1,2-epoxy-1-methylcyclohexane with Cp2TiCl as a model. Rapid evolution of hydrogen gas was demonstrated, indicating that Cp2Ti(H)Cl is indeed a thermally unstable molecule, which undergoes intermolecular reductive elimination of hydrogen under the reaction conditions. The stoichiometry of the reaction (Cp2TiCl:epoxide = 1:1) and the quantity of hydrogen produced (1 mol per 2 mol of epoxide) is consistent with this assertion. The diminished yield of allylic alcohol from these reactions under the conditions of protic versus aprotic catalysis can be understood in terms of the predominant titanium(III) present in solution. Under the conditions of protic catalysis, Cp2TiCl complexes with collidine hydrochloride and the titanium(III) center is less available for "cross-disproportionation" with carbon-centered radicals; this leads to byproducts from radical capture by hydrogen atom transfer, resulting in a saturated alcohol.
Efficient Simmons-Smith cyclopropanation with Zn/Cu and CH 2I2
Fujii, Kanami,Shiine, Kodai,Misaki, Tomonori,Sugimura, Takashi
, p. 69 - 72 (2013/04/23)
An appropriate solvent to perform the original Simmons-Smith reaction was reinvestigated. Among available solvents, cyclopentyl methyl ether (CPME), a recently commercialized ethereal solvent, was found to be the best so far. Compared with Et2O under reflux - the commonest conditions - reaction completion in CPME at 50 °C was about 10 times faster. The product yields and selectivities were mostly identical to those with Et2O, but were better in some cases; e.g. 13-56% with 2-cyclohexenol. The good performance of CPME should be mainly due to its moderate polarity and high boiling point. Copyright
Silicon-based nucleophile mediated one-carbon ring expansion reaction of 1-(trimethylsilylmethyl)cycloalkanecarbaldehydes
Tanino,Sato,Kuwajima
, p. 6551 - 6554 (2007/10/02)
Under the influence of an appropriate Lewis acid, TMS sulfide and TMS-OTf induced one carbon ring expansion of 1-(trimethylsilylmethyl)cycloalkanecarbaldehydes to afford the corresponding 2-methylenecycloalkyl sulfides and ethers, or their isomerized ones
Reaction of Enol Ethers with Zinc Carbenoid Reagents. Cyclopropanation and Subsequent Isomerization to Allylic Ethers
Ryu, Ilhyong,Aya, Tomoyuki,Otani, Shoji,Murai, Shinji,Sonoda, Noboru
, p. 279 - 290 (2007/10/02)
The reactions of enol ethers (ROC=C, R= alkyl, silyl) with zinc carbenoid reagents were found to give allylic ethers in several cases along with the expected cyclopropyl etehrs.The ratio of these two products was highly dependent on the concentration of t
Ring Opening of Oxiranes by Trimethylsilyl Trifluoromethanesulfonate
Murata, Sizuaki,Suzuki, Masaaki,Noyori, Ryoji
, p. 247 - 254 (2007/10/02)
Trimethylsilyl trifluoromethanesulfonate promotes ring opening reactions of oxirane derivatives.The reaction course is highly affected by the structures and substitution pattern of the substrates.Tetra-, tri, and 2,2-disubstituted oxiranes and simple cycloalkene oxides are converted to the corresponding allylic alcohol trimethylsilyl ethers.The overall transformation is interpreted in terms of trans addition of the silyl trifluoromethanesulfonate to the oxirane ring followed by base-promoted anti elimination of a trifluoromethanesulfonic acid element. 2,3-dialkyl- or monoalkyloxiranes isomerize to the corresponding ketones and aldehydes, respectively. (Z)-Cyclooctene oxide undergoes the transannular reaction to give endo-cis-2-trimethylsiloxybicyclooctane.The reaction of 6-methyl-5-hepten-2-one oxide produces 2,2,6-trimethyl-3-trimethylsiloxy-3,4-dihydro-2H-pyran. 1,2-Methyl migration takes place in the reaction of (E)-3α-t-butyldimethylsiloxy-5α-pregnene 17α,20-oxide to afford 3α-t-butyldimethylsiloxy-17β-methyl-17α--18-nor-5α-androst-13(14)-ene. α-Pinene oxide gives trans-carveol trimethylsilyl ether.
TRIMETHYLSILYL TRIFLATE IN ORGANIC SYNTHESIS
Noyori, R.,Murata, S.,Suzuki, M.
, p. 3899 - 3910 (2007/10/02)
Trimethylsilyl triflate is a powerful silylating agent for organic compounds and acts as a catalyst which accelerates a variety of nucleophilic reactions in aprotic media.The reactions proceed via one-center, electrophilic coordination of the silyl group to hetero functional groups and exhibit unique selectivities.
