78043-55-7Relevant academic research and scientific papers
Selective Approaches to α- and β-Arylated Vinyl Ethers
Bolm, Carsten,Domzalska-Pieczykolan, Anna,Funes-Ardoiz, Ignacio,Furman, Bart?omiej
supporting information, (2021/11/30)
We developed simple and efficient protocols for palladium-catalyzed regioselective α- and β-arylations of structurally diverse vinyl ethers. Both catalytic methods proceed under relatively mild reactions conditions applying to a broad substrate range including more complex compounds providing arylated glucal or isochromene. Lacking the common requirement of a large reagent excess, the transformations are highly economic and limiting the waste production. Results from computational studies (DFT) provided insight into the key factors determining the pronounced regioselectivities of the investigated reactions.
(Z)-Selective enol triflation of α-alkoxyacetoaldehydes: Application to synthesis of (Z)-allylic alcohols via cross-coupling reaction and [1,2]-wittig rearrangement
Kurosawa, Fumiya,Nakano, Takeo,Soeta, Takahiro,Endo, Kohei,Ukaji, Yutaka
, p. 5696 - 5703 (2015/06/16)
The stereoselective transformation of α-alkoxyacetoaldehydes to the corresponding (Z)-vinyl triflates was achieved by treatment with phenyl triflimide and DBU. The stereochemistry was explained by the "syn-effect," which was attributed primarily to an σ → π interaction. The β-alkoxy vinyl triflates obtained were applied to the stereoselective synthesis of structurally diverse (Z)-allylic alcohols via transition metal-catalyzed cross-coupling reaction and [1,2]-Wittig rearrangement.
Styryl ether formation from benzyl alcohols under transition-metal-free basic DMSO conditions
Yang, Kai,Song, Qiuling
, p. 2267 - 2272 (2015/03/04)
A phenol-catalyzed aerobic oxidative styryl ether formation method was developed with benzyl alcohol under basic DMSO. Styryl ether was obtained after 12 hours of heating at 60-80 °C where DMSO was involved in the reaction as the extra carbon source. Control experiments indicated that both phenol and DMSO are crucial for the success of the reaction. A variety of styryl ethers were prepared smoothly from benzyl alcohols in good to excellent yields in an environmentally friendly way. This journal is
Trimethyl phosphite as a trap for alkoxy radicals formed from the ring opening of oxiranylcarbinyl radicals. Conversion to alkenes. Mechanistic applications to the study of C-C versus C-O ring cleavage
Ding, Bangwei,Bentrude, Wesley G.
, p. 3248 - 3259 (2007/10/03)
Trimethyl phosphite, (MeO)3P, is introduced as an efficient and selective trap in oxiranylcarbinyl radical (2) systems, formed from haloepoxides 8-13 under thermal AIBN/n-Bu3SnH conditions at about 80 °C. Initially, the transformations of 8-13, in the absence of phosphite, to allyl alcohol 7 and/or vinyl ether 5 were measured quantitatively (Table 1). Structural variations in the intermediate oxiranylcarbinyl (2), allyloxy (3), and vinyloxycarbinyl (4) radicals involve influences of the thermodynamics and kinetics of the C-O (2 → 3, k1) and C-C (2 → 4, k2) radical scission processes and readily account for the changes in the amounts of product vinyl ether (5) and allyl alcohol (7) formed. Added (MeO)3P is inert to vinyloxycarbinyl radical 4 and selectively and rapidly traps allyloxy radical 3, diverting it to trimethyl phosphate and allyl radical 6. Allyl radicals (6) dimerize or are trapped by n-Bu3SnH to give alkenes, formed from haloepoxides 8, 9, and 13 in 69-95% yields. Intermediate vinyloxycarbinyl radicals (4), in the presence or absence of (MeO)3P, are trapped by n-Bu3SnH to give vinyl ethers (5). The concentrations of (MeO)3P and n-Bu3SnH were varied independently, and the amounts of phosphate, vinyl ether (5), and/or alkene from haloepoxides 10, 11, and 13 were carefully monitored. The results reflect readily understood influences of changes in the structures of radicals 2-4, particularly as they influence the C-O (k1) and C-C (k2) cleavages of intermediate oxiranylcarbinyl radical 2 and their reverse (k-1, k-2). Diversion by (MeO)3P of allyloxy radicals (3) from haloepoxides 11 and 12 fulfills a prior prediction that under conditions closer to kinetic control, products of C-O scission, not just those of C-C scission, may result. Thus, for oxiranylcarbinyl radicals from haloepoxides 11, 12, and 13, C-O scission (k1, 2 → 3) competes readily with C-C cleavage (k2, 2 → 4), even though C-C scission is favored thermodynamically.
Non-carbonyl-stabilized metallocarbenoids in synthesis: The development of a tandem rhodium-catalyzed bamford-stevens/thermal aliphatic claisen rearrangement sequence
May, Jeremy A.,Stoltz, Brian M.
, p. 12426 - 12427 (2007/10/03)
A tandem rhodium-catalyzed Bamford-Stevens/Claisen rearrangement is presented. The tandem reaction uses Eschenmoser hydrazones for the in situ generation of non-carbonyl-stabilized diazo alkanes, which are presumably intercepted by Rh(II) catalysts to induce a 1,2-hydride migration. This sequence provides high levels of stereocontrol for the generation of simple acyclic (Z)-enol ethers. These enol ethers undergo either thermal or Lewis acid accelerated Claisen rearrangements to provide products of high diastereopurity. Also presented are cascade reactions, wherein a third chemical step occurs after the initial tandem sequence (i.e., Bamford-Stevens/Claisen/ene and Bamford-Stevens/Claisen/Cope). Copyright
A Novel Probe for Free Radicals featuring Epoxide Cleavage
Dickinson, Julia M.,Murphy, John A.,Patterson, Christopher W.,Wooster, Nicholas F.
, p. 1179 - 1184 (2007/10/02)
This paper describes the identification of carbon-carbon bond cleavage within a defined range of epoxides as being a reaction type which is specifically diagnostic of free radicals adjacent to the epoxide.The speed of the epoxide cleavage is greater than
A Novel Probe for Free-radical Intermediates
Johns, Amanda,Murphy, John A.,Patterson, Christopher W.,Wooster, Nicholas F.
, p. 1238 - 1240 (2007/10/02)
C-C bond cleavage of oxiranes, which is triggered by adjacent homolysis but not heterolysis, occurs at a sufficiently rapid rate to be a useful probe for free-radical intermediates in chemical and biological systems.
An Uncomplicated Synthesis of α-Styrylenol Ethers and Arylacetaldehydes from Benzyl Alcohols
Langhals, Heinz,Julia, Marc,Uguen, Daniel
, p. 2216 - 2222 (2007/10/02)
The reaction of benzyl alcohol with potassium hydroxide in dimethyl sulfoxide yielding (E)-β-(benzyloxy)styrene is described.The mechanism proposed for this reaction was studied by isotope labelling and by introduction of probable intermediates.The reacti
