339591-35-4Relevant academic research and scientific papers
Acyclic Diastereoselection in the Wittig Sigmatropic Rearrangement of a Series of Isomeric Crotyl Ethers. A Conceptual Model for the Transition-State Geometry
Mikami, K.,Kimura, Y.,Kishi, N.,Nakai, T.
, p. 279 - 281 (1983)
The levels of diastereoselection in a broad range of Wittig Variations with different substituents on the carbanion termini have been evaluated and permit us to propose a reasonable model for the transition-state geometry.
Allylation reactions of aldehydes with allylboronates in aqueous media: Unique reactivity and selectivity that are only observed in the presence of water
Kobayashi, Shu,Endo, Toshimitsu,Yoshino, Takumi,Schneider, Uwe,Ueno, Masaharu
supporting information, p. 2033 - 2045 (2013/09/23)
Zn(OH)2-catalyzed allylation reactions of aldehydes with allylboronates in aqueous media have been developed. In contrast to conventional allylboration reactions of aldehydes in organic solvents, the α-addition products were obtained exclusively. A catalytic cycle in which the allylzinc species was generated through a B-to-Zn exchange process is proposed and kinetic studies were performed. The key intermediate, an allylzinc species, was detected by HRMS (ESI) analysis and by online continuous MS (ESI) analysis. This analysis revealed that, in aqueous media, the allylzinc species competitively reacted with the aldehydes and water. An investigation of the reactivity and selectivity of the allylzinc species by using several typical allylboronates (6a, 6b, 6c, 6d) clarified several important roles of water in this allylation reaction. The allylation reactions of aldehydes with allylboronic acid 2,2-dimethyl-1,3-propanediol esters proceeded smoothly in the presence of catalytic amounts of Zn(OH)2 and achiral ligand 4d in aqueous media to afford the corresponding syn-adducts in high yields with high diastereoselectivities. In all cases, the α-addition products were obtained and a wide substrate scope was tolerated. Furthermore, this reaction was applied to asymmetric catalysis by using chiral ligand 9. Based on the X-ray structure of the Zn-9 complex, several nonsymmetrical chiral ligands were also found to be effective. This reaction was further applied to catalytic asymmetric alkylallylation, chloroallylation, and alkoxyallylation processes and the synthetic utility of these reactions has been demonstrated. Still waters run deep: The Zn(OH)2-catalyzed allylation of aldehydes with allylboronates in aqueous media exclusively afford the α-addition products. This reaction was also applied to alkylallylation, chloroallylation, and alkoxyallylation reactions. The role of water is discussed. Copyright
Enhanced anti-diastereo- and enantioselectivity in alcohol-mediated carbonyl crotylation using an isolable single component iridium catalyst
Gao, Xin,Townsend, Ian A.,Krische, Michael J.
supporting information; experimental part, p. 2350 - 2354 (2011/05/30)
The cyclometalated iridium complex (S)-I derived from [Ir(cod)Cl] 2, 4-cyano-3-nitrobenzoic acid, allyl acetate, and (S)-SEGPHOS is conveniently isolated by precipitation or through conventional silica gel flash chromatography. This single-component precatalyst allows alcohol mediated carbonyl crotylations to be performed at significantly lower temperature, resulting in enhanced levels of anti-diastereo- and enantioselectivity. Most significantly, the chromatographically isolated precatalyst (S)-I enables carbonyl crotylations that are not possible under previously reported conditions involving in situ generation of (S)-I.
Anti-diastereo-and enantioselective carbonyl crotylation from the alcohol or aldehyde oxidation level employing a cyclometallated iridium catalyst: α-methyl allyl acetate as a surrogate to preformed crotylmetal reagents
Kim, In Su,Han, Soo Bong,Krische, Michael J.
supporting information; experimental part, p. 2514 - 2520 (2009/08/16)
Under the conditions of transfer hydrogenation employing an ortho-cyclometallated iridium catalyst generated in situ from [Ir(cod)Cl] 2, 4-cyano-3-nitrobenzoic acid and the chiral phosphine ligand (S)-SEGPHOS, α-methyl allyl acetate couples to
AN IMPROVED PROCEDURE FOR THE Cr(II) MEDIATED HOMOALLYLIC ALCOHOL SYNTHESIS
Wuts, Peter G. M.,Callen, Gary R.
, p. 1833 - 1838 (2007/10/02)
An improved procedure was developed for the coupling of allylhalides with algehydes wich utilizes CrCl2 prepared by reduction of CrCl3 with sodium amalgam.
