Strategic use of amino acid N-substituents to limit α-carbon-centered radical formation and consequent loss of stereochemical integrity
作者:Anna K. Croft、Christopher J. Easton、Katherine Kociuba、Leo Radom
DOI:10.1016/s0957-4166(03)00542-1
日期:2003.10
amino acid radicals. Optimized structures of glycine derivatives and related substituted methanes, and the corresponding radicals, were determined with B3-LYP/6-31G(d). Single-point RMP2/6-31G(d) calculations on these structures were then used to obtain radical stabilization energies, which were compared with the relative rates of formation of the same or closely similar radicals in reactions with N-bromosuccinimde
Atroposelective Haloamidation of Indoles with Amino Acid Derivatives and Hypohalides
作者:Zhaojie Li、Menghan Tang、Chenyang Hu、Shouyun Yu
DOI:10.1021/acs.orglett.9b03456
日期:2019.11.1
atroposelective coupling of indoles with chiral amino acid-based sulfonamides mediated by hypohalides is described. A series of 2-amido-3-haloindoles with a C–N chiral axis are delivered using this strategy. The C3 halogen atoms can facilitate further transformation. Various functionalities, such as carbonyl, phosphine, aryl, and alkenyl groups, can be introduced into the C3 position of indoles. These structurally
Ligand-Enabled γ-C(sp<sup>3</sup>)-H Acetoxylation of Triflyl-Protected Amines
作者:Wen-Liang Jia、M. Ángeles Fernández-Ibáñez
DOI:10.1002/ejoc.201800891
日期:2018.12.2
A palladium‐catalyzed γ‐C(sp3)–H acetoxylation of triflyl‐protected amines has been achieved. The use of pyridine or 2‐alkoxyquinoline‐type ligands is key to the success of this transformation. The reaction is highly diastereoselective and easily scalable, and constitutes a direct approach for the synthesis of γ‐hydroxy‐α‐amino acids and β,γ‐dihydroxy amines, which are not readily accessible by other
Ligand-enabled cross-coupling of C(sp3)–H bonds with arylboron reagents via Pd(II)/Pd(0) catalysis
作者:Kelvin S. L. Chan、Masayuki Wasa、Ling Chu、Brian N. Laforteza、Masanori Miura、Jin-Quan Yu
DOI:10.1038/nchem.1836
日期:2014.2
unreactive C–H bonds, chemists have discovered reaction conditions that enable reactions of C(sp2)–H and C(sp3)–Hbonds with a variety of coupling partners. Despite these advances, the development of suitable ligands that enable catalytic C(sp3)–H bond functionalization remains a significant challenge. Herein we report the discovery of a mono-N-protected amino acid ligand that enables Pd(II)-catalysed
Ligand-Enabled γ-C(sp<sup>3</sup>)–H Olefination of Amines: En Route to Pyrrolidines
作者:Heng Jiang、Jian He、Tao Liu、Jin-Quan Yu
DOI:10.1021/jacs.5b13462
日期:2016.2.17
Pd(II)-catalyzed olefination of γ-C(sp(3))-H bonds of triflyl (Tf) and 4-nitrobenzenesulfonyl (Ns) protected amines is achieved. Subsequent aza-Wacker oxidative cyclization or conjugate addition of the olefinated intermediates provides a variety of C-2 alkylated pyrrolidines. Three pyridine- and quinoline-based ligands are developed to match different classes of amine substrates, demonstrating a rare