Results 71 to 80 of about 23,776 (268)

Diastereoselective Spiroannulation of Phenolic Derivatives: Effect of Steric Hindrance on the Diastereoselectivity

International Journal of Chemistry, 2011
This study was aimed at determining the effect, if any, that steric factors may have on the diastereoselectivity in the spiroannulation of simple phenols. A series of phenols bearing different size substituents ortho to the phenolic hydroxyl were synthesized and spiroannulated to the corresponding spiroethers in good to excellent yields (76-94 ...
Guy L Plourde, Lyndia M. Susag
openaire   +2 more sources

Recent Advances in Intramolecular C─N Bond Formation for Pyrrolidine Synthesis. [PDF]

ChemistryOpen
This review highlights synthetic advances (2013–2025) in intramolecular C─N bond formation for constructing the pharmaceutically relevant pyrrolidine core. The review is organized into five methodological clusters: 1) intramolecular alkene/alkyne amination; 2) tandem annulations, which involve C─N bond formation as the key step; 3) nucleophilic ...
Kroņkalne R, Turks M.
europepmc   +2 more sources

Diastereoselective reactions of enolates

, 1996
Triphenylglycol-derived esters 2 and 8a have been applied in asymmetric aldol reactions. The homochiral propionates 7 and 8a have been applied in asymmetric aldol reactions.
Galle, D., Sacha, H., Baskaran, S., Braun, M.   +3 more
core   +1 more source

Triphenylmethyl Group as a Highly Diastereoselective exo,endo-Auxiliary in Double Diels–Alder Reactions with 2H-Pyran-2-ones

Molecules
The influence of steric hindrance caused by the dienophiles on the stereoselectivity of cycloadditions of 2H-pyran-2-ones with maleimides was investigated in this study.
Marko Krivec, Žiga Štirn, Marijan Kočevar, Krištof Kranjc   +3 more
doaj   +1 more source

Fluorine‐Directed Diastereoselective Iodocyclizations

Angewandte Chemie International Edition, 2007
An inside job: β‐Fluorinated lactones and tetrahydrofurans are synthesized by iodocyclization of various allylic fluorides. The fluorine substituent acts as a highly efficient syn‐stereodirecting group for the ring closure. The experimental results combined with theoretical studies provide evidence in support of an “inside fluoro effect” to account for
Tredwell, M, Luft, J, Schuler, M, Tenza, K, Houk, K, Gouverneur, V   +5 more
openaire   +2 more sources

Diastereoselective Formation of Complexed Methylenediphosphiranes [PDF]

Organometallics, 2008
Stable syn-substituted methylenediphosphirane complexes are obtained from the reaction of transient, electrophilic phosphinidenes [R-P=W(CO)
Jansen, Helen, Rosenthal, A.J., Slootweg, J.C., Ehlers, A.W., Lutz, M., Spek, A.L., Lammertsma, K.   +6 more
openaire   +4 more sources

Cobalt‐Catalyzed Radical Ligand Transfer (RLT) Enables Remote‐Markovnikov Hydroamination of Alkenes

Angewandte Chemie International Edition, EarlyView.
A cobalt‐catalyzed remote‐Markovnikov 1,3‐hydroamination of allyl carboxylates proceeds through MHAT, 1,2‐radical acyloxy migration (1,2‐RAM), and radical ligand transfer (RLT) from a Co‐N intermediate, providing protected amino alcohols. ABSTRACT Amino alcohols are prevalent in pharmaceuticals, agrochemicals, and functional materials, yet ...
Arman Khosravi, Ho Martin Yuen, Seth Fremin, Nuwan A. Pannilawithana, Nol Supasueb, Yu Zhang, Peng Liu, Ming‐Yu Ngai   +7 more
wiley   +1 more source

One-Pot Highly Diastereoselective Synthesis of cis-Vinylaziridines via the Sulfur Ylide-Mediated Aziridination and Palladium(0)-Catalyzed Isomerization

, 2010
Highly diastereoselective synthesis of cis-trisubstituted vinylaziridines containing a quaternary carbon center is realized by a one-pot protocol in which the combination of sulfur ylide-mediated aziridination of cyclic ketimines and Pd(0)-catalyzed ...
Zheng, Jun-Cheng, Tang, Yong, Sun, Xiu-Li, Zhu, Ben-Hu, Zhou, Yong-Gui, Yu, Chang-Bin, Shen, Qi, 周永贵   +7 more
core   +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

Pharmaceuticals Made with Hydrogen: A Sustainable and Efficient Approach Using Flow Synthesis

Chemistry – A European Journal, EarlyView.
We demonstrate a sustainable strategy for pharmaceutical manufacturing by combining hydrogen, heterogeneous catalysis, and continuous flow synthesis. The development of novel catalysts and their application in a multi‐step synthesis of donepezil enabled a highly productive process with no intermediate purification.
Shū Kobayashi, Haruro Ishitani
wiley   +1 more source