Results 61 to 70 of about 26,509 (243)

Synthesis of Enantiomerically Pure 2,2,3,4,5-Pentasubstituted Pyrrolidines by Phenylsulfanyl Migration^†

, 2016
Enantiomerically pure 2,2,3,4,5-pentasubstituted pyrrolidines can be prepared, in high overall yield, from α,β-unsaturated esters. Asymmetry is introduced via a Michael addition, and additional stereogenic centers are introduced by an aldol reaction.
I. Craig Baldwin (3066192), David J. Fox (1909222), Paul Briner (3066189), Stuart Warren (2369323), Martin D. Eastgate (1314654)   +4 more
core   +3 more sources

A Straightforward Route to Enantiopure Pyrrolizidines and Indolizidines by Cycloaddition to Pyrroline N-Oxides Derived from the Chiral Pool

Molecules, 1998
Enantiomerically pure, five membered cyclic nitrones, easily obtained in large amounts from protected hydroxyacids and aminoacids such as D- and L-tartaric, L-malic, and L-aspartic acids, give cycloaddition reactions with a good diastereocontrol.
Alberto Brandi, Valentina Fedi, Franca M. Cordero, Stefano Cicchi, Andrea Goti   +4 more
doaj   +1 more source

Convenient access to pyrrolidin-3-ylphosphonic acids and tetrahydro-2H-pyran-3-ylphosphonates with multiple contiguous stereocenters from nonracemic adducts of a Ni(II)-catalyzed Michael reaction

Beilstein Journal of Organic Chemistry, 2020
A new synthetic strategy toward nonracemic phosphoryl-substituted pyrrolidines and tetrahydropyranes with three and five contiguous stereocenters is presented.
Alexander N. Reznikov, Dmitry S. Nikerov, Anastasiya E. Sibiryakova, Victor B. Rybakov, Evgeniy V. Golovin, Yuri N. Klimochkin   +5 more
doaj   +1 more source

Rh(II)/Pd(0) Dual Catalysis: Carbenoid N-H Insertion/Allylation Cascade Reaction to Construct Highly Functionalized and Polysubstituted Pyrrolidines

Molecules
In the category of drugs approved by the U.S. FDA, pyrrolidine is the most frequently used core of five-membered nonaromatic heterocycles containing nitrogen.
Maocheng Tang, Xianyan Jiao, Deping He, Ji-Xing Zhao, Ping Liu, Chun-Tian Li   +5 more
doaj   +1 more source

Late‐Stage Functionalization of Peptides on the Solid Phase

Angewandte Chemie International Edition, EarlyView.
Peptide modifications are essential to control pharmacodynamic and pharmacokinetic properties of peptide drugs. Consequently, strategies that allow for efficient and rapid incorporation of non‐canonical modifications into peptides in parallel formats are highly sought after.
Marius Werner, Truc Lam Pham, Franziska Thomas   +2 more
wiley   +1 more source

Skeletal contraction: A novel strategy to access multisubstituted cyclobutane

Green Synthesis and Catalysis, 2022
The polysubstituted and spirocyclic cyclobutanes were efficiently constructed by the utilization of a novel skeletal contraction strategy which only took one-step synthesis from the readily accessible pyrrolidines.
Chunfa Xu, V.U. Bhaskara Rao, Fen-Er Chen   +2 more
doaj   +1 more source

Pd(II)‐Catalyzed Strategies for the β‐Arylation of α‐Amino Acids: An Overview

Chemistry – A European Journal, EarlyView.
The graphical abstract summarizes the review “Pd(II)‐Catalyzed Strategies for the β‐Arylation of α‐Amino Acids: An Overview”, highlighting representative Pd(II)‐catalyzed methods for the β‐arylation of α‐amino acids. Key mechanistic features, substrate diversity, and synthetic relevance of these transformations are showcased. Abstract Metal‐catalyzed C─
Davide Illuminati, Claudio Trapella, Vinicio Zanirato, Virginia Cristofori, Anna Fantinati   +4 more
wiley   +1 more source

Highly Potent Fluorogenic Ligands for Triplex DNA: 5‐Substituted 2‐(Naphthalen‐2‐yl)‐4H‐Chromen‐4‐Ones

Chemistry – A European Journal, EarlyView.
5‐Substituted 2‐(naphthalen‐2‐yl)‐4H‐chromen‐4‐ones are reported as a novel class of highly potent and selective triplex DNA ligands. These ligands induce triplex formation at submicromolar concentrations and inhibit enzymatic activity via ligand‐mediated triplex formation.
Nghia Tran, Landy Gu, Krege M. Christison, Kalee Thao, Liang Xue   +4 more
wiley   +1 more source

[3 + 2] Cycloaddition on Carbohydrate Templates: Stereoselective Synthesis of Pyrrolidines

, 2016
Pyrrolidine derivatives were prepared in high diastereoselectivities and good yields via a [3 + 2] cycloaddition of a tert-butyldimethylsilyl protected carbohydrate-based allene with a diverse range of imines.
Xue-Wei Liu (736285), Min Li Leow (1863589), Bala Kishan Gorityala (2042737), Jimei Ma (2042734), Shuting Cai (2073592)   +4 more
core   +1 more source

A DFT Study on the Mechanism of Selective Formation of Substituted Azepines From 1‐Azabutadienes and Cyclopropanes

Chemistry – A European Journal, EarlyView.
The origin of the unusual regioselectivity in the Mg‐catalyzed cyclization of azadiene‐type imines with cyclopropanes is elucidated by DFT calculations. Although five‐membered rings are typically favored, energy decomposition analysis reveals that severe steric congestion induces a highly distorted transition state, rendering the five‐membered pathway ...
Ryo Kobayashi, Chao Wang, Shuto Kosuge, Yuji Matsuya, Kenji Sugimoto, Keiichi Hirano   +5 more
wiley   +1 more source