A Mild and General Larock Indolization Protocol for the Preparation of Unnatural Tryptophans
作者:Kangway V. Chuang、Madeleine E. Kieffer、Sarah E. Reisman
DOI:10.1021/acs.orglett.6b02477
日期:2016.9.16
A mild and general protocol for the Pd(0)-catalyzed heteroannulation of o-bromoanilines and alkynes is described. Application of a Pd(0)/P(tBu)3 catalyst system enables the efficient coupling of o-bromoanilines at 60 °C, mitigating deleterious side reactions and enabling access to a broad range of useful unnatural tryptophans. The utility of this new protocol is demonstrated in the highly convergent
Structure and Function of NzeB, a Versatile C–C and C–N Bond-Forming Diketopiperazine Dimerase
作者:Vikram V. Shende、Yogan Khatri、Sean A. Newmister、Jacob N. Sanders、Petra Lindovska、Fengan Yu、Tyler J. Doyon、Justin Kim、K. N. Houk、Mohammad Movassaghi、David H. Sherman
DOI:10.1021/jacs.0c06312
日期:2020.10.14
To identify the molecular basis for the flexible site-, stereo-, and chemoselectivity of NzeB, we obtained high-resolution crystalstructures (1.5Å) of the protein in complex with native and non-native substrates. This, to our knowledge, represents the firstcrystalstructure of an oxidase catalyzing direct, intermolecular C-H amination. Site-directed mutagenesis was employed to assess the role individual
The total synthesis of (-)-aspergilazine A, an alkaloid possessing a rare N1' to C6 bisindole bond, is described. A palladium-catalyzed N-arylation was used to selectively install the N1'-C6 bond in the presence of three other possible arylation sites. The ligand XPhos displayed a unique capability to efficiently carry out the N-arylation while simultaneously suppressing epimerization of the sensitive C9 stereocenters. This total synthesis has confirmed that aspergilazine A is a dimer of brevianamide F.
Two Cytochrome P450 Enzymes from <i>Streptomyces</i> sp. NRRL S-1868 Catalyze Distinct Dimerization of Tryptophan-Containing Cyclodipeptides
作者:Huili Yu、Shu-Ming Li
DOI:10.1021/acs.orglett.9b02666
日期:2019.9.6
Heterologous expression in Streptomyces coelicolor and in vitro enzyme characterization proved that two P450 enzymes, AspB and NasB, from Streptomyces sp. NRRL S-1868 catalyze two new dimerization patterns of tryptophan-containing cyclodipeptides. Structure elucidation of the metabolites revealed an N1-C7' dimer of two cWP molecules as the predominant product of AspB and C3-C7' connected cWP with cWA as that of NasB.
Indole-Indole Ullmann Cross-Coupling for C<sub>Ar</sub>
-N Bond Formation: Total Synthesis of (-)-Aspergilazine A
作者:Iago Alonso、Rosana Alvarez、Ángel R. de Lera
DOI:10.1002/ejoc.201700842
日期:2017.9.8
A new synthetic approach to the heterodimeric bis-Trp/Pro-diketopiperazine alkaloid (–)-aspergilazine A is developed. The method is based on the previously optimized CuI-catalyzed CAr–N Ullmann coupling of indole units.
开发了一种新的合成方法,用于异二聚体bis-Trp / Pro-diketopiperazine生物碱(-)-aspergilazineA。该方法基于先前优化的Cu I催化的吲哚单元的C Ar -N Ullmann偶联。