报道了四种螺环羟吲哚生物碱的外消旋全合成。一般的起始材料是 N-2-丁烯基化的 2-羟色胺,它与官能化的醛进行碱介导的曼尼希螺环化反应以生成 C 环。第二个关键步骤是 Pd 催化的 α-酮酯烯醇化物(在原始醛中)环化到烯丙基碳酸酯(在 N 取代基中)以形成 D 环。关键步骤的立体选择性适中,但异构体易于纯化,可以方便地制备天然产物,其中三个是首次。
Reaction design in asymmetric catalysis has traditionally been predicated on a structurally robust scaffold in both substrates and catalysts, to reduce the number of possible diastereomeric transition states. Herein, we present the stereochemical dynamics in the Ni(II)-catalyzed diastereoconvergent (3 + 2) cycloadditions of isomerizable nitrile-conjugated nitrones with α-ketoesterenolates. Even in
Asymmetric Synthesis of Diverse Glycolic Acid Scaffolds via Dynamic Kinetic Resolution of α-Keto Esters
作者:Kimberly M. Steward、Michael T. Corbett、C. Guy Goodman、Jeffrey S. Johnson
DOI:10.1021/ja3102709
日期:2012.12.12
The dynamickineticresolution of α-keto esters via asymmetric transfer hydrogenation has been developed as a technique for the highly stereoselective construction of structurally diverse β-substituted-α-hydroxy carboxylic acid derivatives. Through the development of a privileged m-terphenylsulfonamide for (arene)RuCl(monosulfonamide) complexes with a high affinity for selective α-keto ester reduction
Total synthesis and biological evaluation of atrop-O-benzyl-desmethylabyssomicin C
作者:R. Matovic、F. Bihelovic、M. Gruden-Pavlovic、R. N. Saicic
DOI:10.1039/c4ob01436g
日期:——
The total synthesis of desmethylabyssomicin C analogue 1 was accomplished using diastereotopos-selective ring closing metathesis and Nozaki–Hiyama–Kishi cyclization as the key steps. The synthetic analogue retained its antibacterial activity against methicillin-resistant S. aureus strains, whereas its cytotoxicity decreased for three orders of magnitude, as compared to atrop-abyssomicin C.
efficient, asymmetric, catalytic, triple-cascade reaction between α-keto esters and nitroalkenes to construct cyclohexanes with six vicinal stereogenic centers in good yields and with high enantioselectivities has been established. A bifunctional guanidine–amide organocatalyst proved to be useful for the Michael/Michael/Henry sequence through Bronsted base and hydrogen-bonding cooperativecatalysis.
The Direct Asymmetric Vinylogous Aldol Reaction of Furanones with α-Ketoesters: Access to Chiral γ-Butenolides and Glycerol Derivatives
作者:Jie Luo、Haifei Wang、Xiao Han、Li-Wen Xu、Jacek Kwiatkowski、Kuo-Wei Huang、Yixin Lu
DOI:10.1002/anie.201006316
日期:2011.2.18
Twice as good: The title reaction using the tryptophan‐derived bifunctional organic catalyst 1 has been developed. The reported method led to the synthesis of chiral γ‐substituted butenolides in excellent yields, with high diastereo‐ and enantioselectivities. Facile synthesis of chiralglycerolderivatives containing a tertiary hydroxy group has also been demonstrated.