50585-08-5Relevant academic research and scientific papers
SN2 Reaction of Diarylmethyl Anions at Secondary Alkyl and Cycloalkyl Carbons
Shinohara, Riku,Ogawa, Narihito,Kawashima, Hidehisa,Wada, Kyohei,Saito, Shun,Yamazaki, Takashi,Kobayashi, Yuichi
, p. 1461 - 1478 (2019/01/25)
The substitution reaction of the diethyl allylic and propargylic phosphates with Ar2CH anions was applied to sec-alkyl phosphates to compare reactivity and stereoselectivity. However, the substitution took place on the ethyl carbon of the diethyl phosphate group. We then found that the diphenyl phosphate leaving group ((PhO)2PO2) was suited for the substitution at the sec-alkyl carbon. Enantioenriched diphenyl sec-alkyl phosphates with different substituents (Me, Et, iPr) on the vicinal position underwent the substitution reaction with almost complete inversion (>99% enantiospecificity). The substitution reactions of cyclohexyl phosphates possessing cis or trans substituents (Me and/or tBu) at the C4, C3, and C2 positions of the cyclohexane ring were also studied to observe the difference in reactivity among the cis and trans isomers. A transition-state model with the phosphate leaving group ((PhO)2PO2) in the axial position was proposed to explain the difference. This model was supported by computational calculation of the virtual substitution reaction of the structurally simpler “dimethyl” cyclohexyl phosphates (leaving group = (MeO)2PO2) with MeLi. Furthermore, the calculation unexpectedly indicated higher propensity of (PhO)2PO2 as a leaving reactivity than alkyl phosphate groups such as (MeO)2PO2 and (iPrO)2PO2.
Synthetic utility of tribenzyltin hydride and its derivatives as easily accessible, removable, and decomposable organotin reagents
Yamakawa, Takeshi,Kinoshita, Hidenori,Miura, Katsukiyo
supporting information, p. 129 - 134 (2013/03/13)
Radical reactions using tribenzyltin hydride (Bn3SnH) easily prepared from tin and benzyl chloride were studied. The Et3B- initiated reduction and cyclization of haloalkanes and haloalkenes with Bn 3SnH proceeded efficiently. Homolytic hydrostannylation of alkynes with Bn3SnH followed by treatment with electrophiles gave functionalized alkenes in good to high yields. The organotin byproducts formed could be easily removable by filtration and silica-gel column chromatography without any pretreatment. It was also found that tribenzyltin chloride (Bn 3SnCl) easily decomposed to benzyl alcohol in a basic solution of H2O2.
Modern Friedel-Crafts chemistry. Part-271. Alkylation of benzene with 1-benzyl- and 1-phenylcyclohexanols in the presence of H 2SO4 and AlCl3/CH3NO2 catalysts
Khalaf, Ali A.,Awad, Ibrahim M.,El-Emary, Talaat I.,Abd El-Aal, Hassan A. K.
, p. 1018 - 1022 (2007/10/03)
The alkylation of benzyene with 1-benzylcyclohexanol (3) gave a mixture of 2,3-benzobicyclo[3.3.1]nona-2-ene (8, 79%) and cyclohexyldiphenylmethane (10, 21%) with AlCl3/CH3NO2 catalyst and a mixture of 1-benzylcyclohexene 5 (47.5%), 8 (8%), 10 (21.5%), 1-cyclopentyl-1,2- diphenylethane (12, 18%) and 1-benzyl-1-phenylcyclohexene (13, 4%) with H 2SO4 catalyst. Treatment of 3 with AlCl 3/CH3NO2 in petroleum ether gave a mixture of 5 (26%) and 8 (62%). Attempted alkylation of benzene with 1-phenylcyclohexanol (4) in the presence of either AlCl3/CH3NO2 or H2SO4 catalyst gave 1-(1-phenylcyclohexyl)-2- phenylcyclohexene (17) as sole product. Mechanistic interpretation of the results in terms of carbocation behaviour is offered.
Synthetic radical reactions using dibutylchlorogermane and dibutylethoxygermane as radical mediators
Miura, Katsukiyo,Ootsuka, Kazunori,Hosomi, Akira
, p. 3151 - 3153 (2007/10/03)
In the presence of Et3B as radical initiator, dibutylchlorogermane (1a) and dibutylethoxygermane (1b) reacted with bromo- and iodoalkanes at room temperature to give the corresponding alkanes in high yields. Hydrogermane 1a was more reactive than 1b. However, 1b worked as a better radical mediator in intermolecular radical addition of haloalkanes to electron-deficient alkenes. Georg Thieme Verlag Stuttgart.
A new class of chiral organogermanes derived from C2-symmetric dithiols: Synthesis, characterization and stereoselective free radical reactions
Gualtieri, Giovanna,Geib, Steven J.,Curran, Dennis P.
, p. 5013 - 5019 (2007/10/03)
A new class of dithiostannanes and dithiogermanes have been prepared from 1,1′-binaphthyl-2,2′-dithiol and 3,3′-bis(trimethylsilyl)-1,1′ -binaphtho-2,2′-dithiol. While reduction of 4-butyl-4-chloro-3,5-dithia-4-stanna-cyclohepta[2,1-a;3,4- a′]dinaphthalen
Fluorous tin hydrides: A new family of reagents for use and reuse in radical reactions
Curran, Dennis P.,Hadida, Sabine,Kim, Sun-Young,Luo, Zhiyong
, p. 6607 - 6615 (2007/10/03)
Eight members of a new family of highly fluorinated (fluorous) tin hydrides have been synthesized and studied as reagents for radical reactions. Tin hydrides of the general formulas [Rf(CH2)n]3SnH and [Rf-(CH2)
Rate constants for reaction of a fluorous tin hydride reagent with primary alkyl radicals
Horner, John H.,Martinez, Felix N.,Newcomb, Martin,Hadida, Sabine,Curran, Dennis P.
, p. 2783 - 2786 (2007/10/03)
Rate constants for 6-exo cyclization of the 7,7-diphenyl-6-heptenyl radical (3) in benzotrifluoride (BTF, PhCF3) were determined by laser flash photolysis, and radical clock 3 was used in competition kinetic studies for determination of rate co
CONTRASTING CHEMISTRY OF DIPHENYLCARBENE AND FLUORENYLIDENE IN CYCLOHEXANE
Savino, T. G.,Senthilnathan, V. P.,Platz, M. S.
, p. 2167 - 2180 (2007/10/02)
The chemistry of diphenylcarbene and fluorenylidene in cyclohexane was investigated.An examination of the product distributions, radical scavening experiments and isotopic fractionation established that diphenylcarbene reacts with cyclohexane predominantly, if not exclusively, through its triplet state whereas fluorenylidene exhibits substantial chemistry from its low lying singlet state in addition to some triplet chemistry.The results indicate that the singlet-triplet splitting of fluorenylidene is smaller than in diphenylcarbene.The chemical studies are in accord with previous laser flash photolysis experiments.
