931-77-1Relevant academic research and scientific papers
Stereoselective α-Tertiary Alkylation of N -(Arylacetyl)oxazolidinones
Shim, Eunjae,Zakarian, Armen
supporting information, p. 683 - 686 (2020/04/07)
A method has been developed for the α-tertiary alkylation of zirconium enolates of N -(arylacetyl)oxazolidinones. This reaction directly installs an all-carbon quaternary center vicinal to a benzylic tertiary carbon in a highly diastereoselective manner.
Dual nickel- and photoredox-catalyzed reductive cross-coupling of aryl vinyl halides and unactivated tertiary alkyl bromides
Yu, Weijie,Chen, Long,Tao, Jiasi,Wang, Tao,Fu, Junkai
supporting information, p. 5918 - 5921 (2019/05/27)
A novel reductive cross-coupling of aryl vinyl halides and unactivated tertiary alkyl bromides has been realized via photoredox/nickel dual catalysis to produce vinyl arene derivatives bearing all-carbon quaternary centers with excellent E-selectivity. A stoichiometric metal reductant could be avoided by employing commercially available N,N,N′,N′-tetramethylethylenediamine (TMEDA) as the terminal reductant.
Silica gel-mediated hydrohalogenation of unactivated alkenes using hydrohalogenic acids under organic solvent-free conditions
Tanemura, Kiyoshi
supporting information, p. 4293 - 4298 (2018/11/10)
Silica gel-mediated hydrochlorination of unactivated alkenes using 35% hydrochloric acid under organic solvent-free conditions proceeded to give the corresponding chlorides in good yields. Hydrobromination or hydriodination using 47% hydrobromic acid or 55% hydriodic acid afforded the corresponding halides, respectively. Silica gel could be recycled five times without any significant loss of activities.
Silicon-Carbon Bond Formation via Nickel-Catalyzed Cross-Coupling of Silicon Nucleophiles with Unactivated Secondary and Tertiary Alkyl Electrophiles
Chu, Crystal K.,Liang, Yufan,Fu, Gregory C.
supporting information, p. 6404 - 6407 (2016/06/09)
A wide array of cross-coupling methods for the formation of C-C bonds from unactivated alkyl electrophiles have been described in recent years. In contrast, progress in the development of methods for the construction of C-heteroatom bonds has lagged; for
Boron Tribromide-Assisted Chiral Phosphoric Acid Catalyst for a Highly Enantioselective Diels-Alder Reaction of 1,2-Dihydropyridines
Hatano, Manabu,Goto, Yuta,Izumiseki, Atsuto,Akakura, Matsujiro,Ishihara, Kazuaki
supporting information, p. 13472 - 13475 (2015/11/10)
BBr3-chiral phosphoric acid complexes are highly effective and practical Lewis acid-assisted Bronsted acid (LBA) catalysts for promoting the enantioselective Diels-Alder (DA) reaction of α-substituted acroleins and α-CF3 acrylate. In particular, the DA reaction of α-substituted acroleins with 1,2-dihydropyridines gave the corresponding optically active isoquinuclidines with high enantioselectivities. Moreover, transformations to the key intermediates of indole alkaloids, catharanthine and allocatharanthine, are demonstrated.
Site-selective aliphatic C-H bromination using N -bromoamides and visible light
Schmidt, Valerie A.,Quinn, Ryan K.,Brusoe, Andrew T.,Alexanian, Erik J.
supporting information, p. 14389 - 14392 (2014/12/10)
Transformations that selectively functionalize aliphatic C-H bonds hold significant promise to streamline complex molecule synthesis. Despite the potential for site-selective C-H functionalization, few intermolecular processes of preparative value exist. Herein, we report an approach to unactivated, aliphatic C-H bromination using readily available N-bromoamide reagents and visible light. These halogenations proceed in useful chemical yields, with substrate as the limiting reagent. The site selectivities of these radical-mediated C-H functionalizations are comparable (or superior) to the most selective intermolecular C-H functionalizations known. With the broad utility of alkyl bromides as synthetic intermediates, this convenient approach will find general use in chemical synthesis.
Revisiting the bromination of c-h bonds with molecular bromine by using a photo-microflow system
Manabe, Yoshiyuki,Kitawaki, Yuriko,Nagasaki, Masahiro,Fukase, Koichi,Matsubara, Hiroshi,Hino, Yoshiko,Fukuyama, Takahide,Ryu, Ilhyong
supporting information, p. 12750 - 12753 (2015/03/30)
The photobromination of C-H bonds by using molecular bromine was reinvestigated under microfluidic conditions. The continuous-flow method suppressed the production of dibrominated compounds and effectively produced the desired monobrominated products with high selectivity. Rapid bromination of benzylic substrates containing a photoaffinity azide group was achieved without any decomposition. Go with the (micro)flow: Photobromination of C-H bonds by using molecular bromine under microfluidic conditions has been investigated (see scheme). The continuous-flow method suppressed the production of dibrominated compounds and effectively produced the desired monobrominated compounds with high selectivity. Rapid bromination of benzylic substrates containing a photoaffinity azide group was achieved without any decomposition.
Phosphine-catalyzed reductions of alkyl silyl peroxides by titanium hydride reducing agents: Development of the method and mechanistic investigations
Harris, Jason R.,Haynes, M. Taylor,Thomas, Andrew M.,Woerpel
supporting information; experimental part, p. 5083 - 5091 (2010/10/19)
(Figure presented) A method that allows for the reduction of protected hydroperoxides by employing catalytic amounts of phosphine is presented. The combination of a titanium(IV) alkoxide and a siloxane allowed for the chemoselective reduction of phosphine oxides in the presence of alkyl silyl peroxides. Subsequent reduction of the peroxide moiety by phosphine provided the corresponding silylated alcohols in useful yields. Mechanistic experiments, including crossover experiments, support a mechanism in which the peroxide group was reduced and the silyl group was transferred in a concerted step. Labeling studies with 17O-labeled peroxides demonstrate that the oxygen atom adjacent to the silicon atom is removed from the silyl peroxide.
Silver-catalyzed benzylation and allylation of tertiary alkyl bromides with organozinc reagents
Mitamura, Yukihiro,Asada, Yoshihiro,Murakami, Kei,Someya, Hidenori,Yorimitsu, Hideki,Oshima, Koichiro
experimental part, p. 1487 - 1493 (2011/07/07)
Silver salts catalyze the benzylation and allylation of tertiary alkyl bromides with organozinc reagents. The reactions create quaternary carbon centers efficiently. Treatment of gem-dibromoalkanes with benzylic or allylic zinc reagents under silver catalysis leads to dibenzylation or diallylation. The functional-group compatibility of the present reactions is wider than that of the previous reactions with Grignard reagents.
Kinetics and mechanism of unimolecular heterolysis of cage-like compounds: XIX. Effect of the nucleofuge nature on the activation parameters of heterolysis of 1-halo-1-methylcyclohexanes in cyclohexane. Heterolysis rate ratio in aprotic and protic solvents
Dvorko,Koshchii,Ponomareva
, p. 50 - 55 (2007/10/03)
Heterolysis of 1-bromo-1-methylcyclohexane in cyclohexane (E1 reaction) involves solvation of the transition state (ΔS≠ = -81 J mol-1K-1), while heterolysis of 1-chloro-1- methylcyclohexane is characterized by desolvation of the transition state (ΔS≠ = 92 J mol-1K-1). The probability for the formation of transition state (interaction between cationoid intermediate and solvent cavity) increases in the first case due to enhanced stability of the solvated intermediate, and in the second, due to reduction in its size. The bromide/chloride heterolysis rate ratio decreases as the ionizing power of aprotic solvent decreases and that of protic solvent increases.
