Highly stereoselective synthesis of 1,3-aminoalcohols via Mannich reactions
摘要:
Diastereoselective synthesis of beta-amino ketones by a one-pot Mannich reaction and their subsequent reduction afforded sterically congested enantiomerically pure 1,3-aminoalcohols in high diastereoselectivity: dr up to >98:<2 over two steps. The absolute configurations of the newly created stereogenic centers were assigned by NMR spectroscopy and chemical correlation. (C) 1999 Elsevier Science Ltd. All rights reserved.
Iridium(I) complexes having an imidazol-2-ylidene ligand with benzylic wingtips efficiently catalyzed the β-alkylation of secondary alcohols with primary alcohols and acceptorless dehydrogenative cyclization of 2-aminobenzyl alcohol with ketonesthrough a borrowinghydrogen pathway. The β-alkylated alcohols, including cholesterol derivatives, and substituted quinolines were obtained in good yields
A general and highly efficient method for asymmetric sequential hydrogenation of α,β-unsaturated ketones has been developed by using an iridium/f-Ampha complex as the catalyst, furnishing corresponding chiral alcohols with two contiguous stereocenters in high yields with excellent diastereo- and enantioselectivities (up to 99% yield, >20 : 1 dr and >99% ee). Control experiments indicated that the CC
通过使用铱/f-Ampha 配合物作为催化剂,开发了一种通用且高效的 α,β-不饱和酮的不对称顺序氢化方法,以高收率提供具有两个连续立体中心的相应手性醇,并具有优异的非对映和对映选择性(高达 99% 的产率,>20 : 1 dr 和 >99% ee)。对照实验表明,烯酮的 C C 和 C O 键依次氢化,最终的立体选择性由酮的动态动力学拆分决定。此外,DFT 计算表明,外球途径参与了 C C 和 C的减少。O 烯酮键。该方法的合成效用通过克级反应和极低催化剂负载量 (S/C = 20 000) 和获得抗哮喘药物 CP-199,330 的关键手性中间体的简明合成路线得到证明。
Asymmetric Transfer Hydrogenation of Arylidene-Substituted Chromanones and Tetralones Catalyzed by Noyori–Ikariya Ru(II) Complexes: One-Pot Reduction of C═C and C═O bonds
作者:Guilherme S. Caleffi、Juliana de O. C. Brum、Angela T. Costa、Jorge L. O. Domingos、Paulo R. R. Costa
DOI:10.1021/acs.joc.0c02981
日期:2021.3.19
3-Arylidenechroman-4-ones and 2-arylidene-1-tetralones are hydrogenated to cis-benzylic alcohols in dr’s and er’s up to 99:1 via a C═C and C═O one-pot reduction in the presence of 2–5 mol % Noyori–Ikariya-type RuII chiral complexes and HCO2Na as a hydrogen source under asymmetric transfer hydrogenation–dynamic kinetic resolution (ATH-DKR) conditions. The oxidation of theses substrates resulted in the
Palladium on Charcoal plus Enantiopure Amino Alcohols as Catalytic Systems for the Enantioselective 1,4-Reduction of α-Substituted α,β-Unsaturated Ketones