[4 + 2]-Annulations of Chiral Organosilanes: Application to the Total Synthesis of Leucascandrolide A
作者:Qibin Su、Les A. Dakin、James S. Panek
DOI:10.1021/jo0610412
日期:2007.1.1
Complete details of an asymmetric synthesis of leucascandrolide A (1) are described. The synthesis highlights the use of two diastereoselective [4 + 2]-annulations for the assembly of the functionalized bispyranyl macrolide 3. An efficient assembly and union of the oxazole-containing side chain 4 with macrolide 3 was carried out using a Mitsunobu reaction. A convergent route to the oxazole side chain
Synthesis of γ-Hydroxy-α-amino Acid Derivatives by Enzymatic Tandem Aldol Addition–Transamination Reactions
作者:Carlos J. Moreno、Karel Hernández、Simon J. Charnok、Samantha Gittings、Michael Bolte、Jesús Joglar、Jordi Bujons、Teodor Parella、Pere Clapés
DOI:10.1021/acscatal.1c00210
日期:2021.4.16
benzaldehyde lyase from Pseudomonas fluorescens Biovar I (BAL) to transform the benzaldehyde formed into benzoin, minimizing equilibrium limitations, and (iii) l-Glu as an amine donor with a double cascade comprising branched-chain α-amino acid aminotransferase (BCAT) and aspartate amino transferase (AspAT), both from E. coli, using l-Asp as a substrate to regenerate l-Glu. The γ-hydroxy-α-amino acids thus
报道了通过串联羟醛加成-转氨基一锅两步反应生成 γ-羟基-α-氨基酸的三种酶促途径。该方法设有对映选择性醛醇加成丙酮酸向由催化的各种非芳香醛反式- ö从-hydroxybenzylidene丙酮酸水合酶-醛缩酶(HBPA)恶臭假单胞菌。这提供了手性 4-羟基-2-氧代酸,随后使用S-选择性转氨酶对映选择性胺化。研究了涉及不同胺供体和转氨酶的三种转氨过程:(i)l- Ala 作为具有丙酮酸循环的胺供体,(ii)使用来自荧光假单胞菌的苯甲醛裂解酶的苄胺供体Biovar I (BAL) 将形成的苯甲醛转化为安息香,最大限度地减少平衡限制,以及 (iii) l -Glu 作为胺供体,具有包含支链 α-氨基酸氨基转移酶 (BCAT) 和天冬氨酸氨基转移酶 (AspAT) 的双级联反应),均来自大肠杆菌,使用l -Asp 作为底物再生l -Glu。由此获得的γ-羟基-α-氨基酸被转化为手性α-氨基-γ
The selective inhibition of phosphatases by natural toxins: the anhydride domain of tautomycin is not a primary factor in controlling PP1/PP2A selectivity
作者:Wen Liu、James E. Sheppeck、David A. Colby、Hsien-Bin Huang、Angus C. Nairn、A.Richard Chamberlin
DOI:10.1016/s0960-894x(03)00105-7
日期:2003.5
Analogues of the potent and moderately selective PP1/PP2A inhibitor tautomycin (TM) were prepared with modifications in the C1'-C7' anhydride moiety. While all retain varying degrees of activity within a 3000-fold range of potencies, they also show remarkable constancy in their IC50 ratios, suggesting that the anhydride moiety is not critical in controlling the selectivity of inhibition. (C) 2003 Elsevier Science Ltd. All rights reserved.
A new, short and efficient synthesis of both enantiomers of carnitine
作者:F.D. Bellamy、M. Bondoux、P. Dodey
DOI:10.1016/s0040-4039(00)88555-x
日期:1990.1
A short, efficient and enantioselective synthesis of both (R) and (S) enantiomers of carnitine is reported starting with (R) or (S) malic acid and involving a chemoselective reduction step.
A Convergent Synthesis of the Macrocyclic Core of Cytotrienins: Application of RCM for Macrocyclization
作者:Gwilherm Evano、Jennifer V. Schaus、James S. Panek
DOI:10.1021/ol036284k
日期:2004.2.1
[reaction: see text] The asymmetric synthesis of the fully elaborated macrocyclic core of cytotrienins A-D, potent apoptosis-inducing agents, is described. Synthetic highlights include the construction of the aniline bond using a copper-mediated amidation and the use of a ring-closing metathesis (RCM) reaction to efficiently install the (E,E,E)-triene and simultaneously construct the macrocyclic lactam