52497-55-9Relevant academic research and scientific papers
Nickel-Catalyzed Regioselective Arylboration of Conjugated Dienes
Li, Haoyang,Long, Jiao,Li, Yuqiang,Wang, Wang,Pang, Hailiang,Yin, Guoyin
supporting information, p. 1424 - 1428 (2021/02/26)
The nickel-catalyzed arylboration of conjugated dienes is reported. Good 1,4-regioselectivity and (E)-stereoselectivity were obtained using isoprene, together with very good 1,2-regioselectivity and (E)-stereoselectivity using 1-arylbutadienes. The high reactivity and selectivity of this process were dependent on the use of the appropriate nitrogen-based ligand. Moreover, wide functional group tolerance was observed under mild reaction conditions. This protocol provides a path to allyl or homoallyl boronic ester derivatives starting from 1,3-dienes, aryl bromides, and B2pin2. The downstream transformation of allyl boronic esters was also achieved, suggesting a strategy for the diastereoselective 1,2-difunctionalization of isoprene and demonstrating the potential for the synthesis of complex molecules.
Gold-Catalyzed Asymmetric Thioallylation of Propiolates via Charge-Induced Thio-Claisen Rearrangement
Kim, Hanbyul,Jang, Jiwon,Shin, Seunghoon
supporting information, p. 20788 - 20795 (2020/11/27)
A gold(I)-catalyzed enantioselective thioallylation of propiolates with allyl sulfides is described. The key mechanistic element is a sulfonium-induced Claisen rearrangement which helps minimize the allyl dissociation and render higher enantioselectivity. This protocol features remarkable scope of the allyl moiety, allowing enantiocontrolled synthesis of all-carbon quaternary centers, and exhibits exceptional functional group compatibility with many Lewis bases and π-bonds. This intermolecular variant of Claisen rearrangement forges both C-S and C-C bonds concomitantly, providing efficient access to interesting optically active organosulfur compounds which can be transformed further through the vinyl sulfide as a functional handle. The rate of the reaction was zeroth order with respect to allyl sulfides, which suggested a reversible inhibition, providing a resting state for the catalyst. The Hammett plot displayed a correlation with σp values, suggesting a turnover-limiting sigmatropic rearrangement where decreased electron-density on sulfur accelerated the rearrangement.
Transition-Metal-Free Allylic Borylation of 1,3-Dienes
Maza, Ricardo J.,Davenport, Elliot,Miralles, Núria,Carbó, Jorge J.,Fernández, Elena
supporting information, p. 2251 - 2255 (2019/04/10)
This work explains the reactivity of diboron reagents with 1,3-dienes in a transition-metal-free context. The sole addition of Na2CO3 (30 mol %) to bis(pinacolato)diboron in MeOH allows the 1,4-hydroboration of cyclic and noncyclic 1,3-dienes. The electronic influence on the substrate guarantees the conjugated 1,4-hydroboration versus 1,2-diboration. DFT calculations show that the distribution of charge in the allylic anion intermediate governs the selectivity toward 1,4-hydroboration, while the favored trans configuration in diene reagents determines the preference for the E allyl boronate products.
Regioselective Arylboration of Isoprene and Its Derivatives by Pd/Cu Cooperative Catalysis
Smith, Kevin B.,Kevin Brown
supporting information, p. 7721 - 7724 (2017/06/21)
A method for the regioselective arylboration of isoprene and its derivatives is presented. These reactions allow for the synthesis of useful building blocks from simple components. Through these studies, an unusual additive effect with DMAP has been uncovered that allows for altered reactivity and the formation of quaternary carbon centers. The utility of this method is demonstrated toward the formal synthesis of mesembrine.
Rearrangement Reactions Leading to Optically Active α,α-Disubstituted Primary Allylamines
Hennum, Martin,Odden, Hege Hortemo,Gundersen, Lise-Lotte
, p. 846 - 860 (2017/02/15)
Synthetic routes to α,α-disubstituted allylamines have been examined. Racemic compounds were conveniently prepared by thermal Overman rearrangements of primary allylic alcohols with trisubstituted double bonds, but rearrangement of these substrates using
Enantioselective Palladium-Catalyzed Alkenylation of Trisubstituted Alkenols to Form Allylic Quaternary Centers
Patel, Harshkumar H.,Sigman, Matthew S.
supporting information, p. 14226 - 14229 (2016/11/13)
In this report, we describe the generation of remote allylic quaternary stereocenters β, γ, and δ relative to a carbonyl in high enantioselectivity. We utilize a redox-relay Heck reaction between alkenyl triflates and acyclic trisubstituted alkenols of varying chain-lengths. A wide array of terminal (E)-alkenyl triflates are suitable for this process. The utility of this functionalization is validated further by conversion of the products, via simple organic processes to access remotely functionalized chiral tertiary acid, amine, and alcohol products.
SYNTHESIS AND SOME REACTIONS OF ISOPROPENYLOXIRANE
Gevorkyan, A. A.,Kazaryan, P. I.,Avakyan, S. V.
, p. 372 - 378 (2007/10/02)
A convenient method for the synthesis of isopropenyloxirane by dehydrohalogenation of halohydrins obtained by isomerization of 1-halo-3-methyl-2,3-epoxybutanes was developed.The reactions of isopropenyloxirane with alcohols, water, secondary amines, hydrogen halides, dichlorocarbene, acetic acid anhydrides, and Grignard reagents were studied.
