Homocarbonates as Substrates for the Enantioselective Enzymatic Protection of Amines

Atom‐economy Synthesis of N‐Substituted Carbamate from Urea Derivative and Dimethyl Carbonate Catalyzed by La/SiO2: Characterization and Activity

“…[12][13][14][15][16][17] Also, dimethyl carbonate as a green carbonylation reagent has attracted extensive attention. [18][19][20][21] Apart from carbon monoxide and dimethyl carbonate, carbon dioxide should be an ideal carbonyl source in chemical industry. In addition to its nontoxic character, the release of "green house" gas could be reduced if carbon dioxide as carbonyl source can be realized.…”

Recent Development on the Synthetic Methods of Chiral Indoline Derivatives

“…但吲哚 啉衍生物的外消旋体在用酶拆分时, 只有很少量的酶能 得到较好的 ee 值, 而且在用枯草蛋白酶作生物催化剂 时虽 ee 值很高, 但转化率较低 [3] . 1996 年, Wong 等 [6] 首 次报道了通过脂肪酶和蛋白酶对 N 原子进行选择性的 酰化而实现 2-位取代吲哚啉 7 的动力学拆分的方法 (Scheme 1), 反应得到了较高的 ee 值, 但是产率较低 (93% ee, 6% yield). 尽管酶参与的动力学拆分有较多报道, 但由于其工 业化水平低和浓度增大时适应性差的缺点, 限制了其实 际应用.…”

Direct Asymmetric Hydrosilylation of Indoles: Combined Lewis Base and Brønsted Acid Activation

“…[2] While a variety of protocols, including traditional enzymatic or non-enzymatic kinetic resolutions, [3] and organicmolecule-or metal-mediated asymmetric transformations [4] have been described, the direct asymmetric reduction of prochiral indole precursors would be one of the most straightforward ways to make chiral indolines.[5] Thus, a few transition metal/chiral phosphine complexes, including Rh, Ru, and Ir, have been applied by the groups of Kuwano, Feringa, Pfaltz, and others to the asymmetric hydrogenation of indoles, but the methods usually suffer from a limited substrate scope and relatively harsh reaction conditions.[6] A noteworthy breakthrough was made by Zhou, Zhang, and coworkers who reported an elegant palladium-catalyzed enantioselective hydrogenation of unprotected indoles activated by Brønsted acids. [7] In contrast, Rueping et al presented the chiral Brønsted acid catalyzed transfer hydrogenation of 3H-indoles with Hantzsch dihydropyridine as the hydrogen source.…”

“…[2] While a variety of protocols, including traditional enzymatic or non-enzymatic kinetic resolutions, [3] and organicmolecule-or metal-mediated asymmetric transformations [4] have been described, the direct asymmetric reduction of prochiral indole precursors would be one of the most straightforward ways to make chiral indolines.…”

“…[2] While a variety of protocols, including traditional enzymatic or non-enzymatic kinetic resolutions, [3] and organicmolecule-or metal-mediated asymmetric transformations [4] have been described, the direct asymmetric reduction of prochiral indole precursors would be one of the most straightforward ways to make chiral indolines. [5] Thus, a few transition metal/chiral phosphine complexes, including Rh, Ru, and Ir, have been applied by the groups of Kuwano, Feringa, Pfaltz, and others to the asymmetric hydrogenation of indoles, but the methods usually suffer from a limited substrate scope and relatively harsh reaction conditions.…”