Results 51 to 60 of about 8,448 (224)

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

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

Highly Enantio‐ and Diastereoselective Synthesis of Tetrahydrofuran Frameworks via Chiral Lewis Acid‐Catalyzed Formal [3+2] Cycloaddition of Allylsilanes

Angewandte Chemie International Edition, EarlyView.
The first catalytic asymmetric formal [3+2] cycloaddition of allylsilanes delivers cis‐2,5‐disubstituted tetrahydrofuran‐3‐ones that serve as versatile intermediates for the synthesis of diverse bioactive scaffolds. ABSTRACT A formal [3+2] cycloaddition via cyclization/1,2‐hydride shift initiated by nucleophilic attack of allylsilanes has been ...
Hosung Lee, Dong Kyu Kim, Pingshan Xin, Jin Won Lee, Terim Seo, Do Hyun Ryu   +5 more
wiley   +1 more source

Diastereoselective Reformatsky Reaction Mediated by Dichlorocyclopentadienyltitanium(III)

Molecules
The Reformatsky reaction, first reported in 1887, has long been recognized as a fundamental method for carbon–carbon bond construction due to its mild conditions and functional group tolerance. Over the past few decades, this transformation has undergone
Josefa L. López-Martínez, Irene Torres-García, Manuel Muñoz-Dorado, Miriam Álvarez-Corral, Ignacio Rodríguez-García   +4 more
doaj   +1 more source

Photogenerated Oxetanes as a Gateway to Uphill Cyclopropanation

Angewandte Chemie International Edition, EarlyView.
An atom‐economical route to densely functionalized cyclopropanes from furans and photochemically activated aldehydes is enabled by a unique oxetane‐to‐cyclopropane rearrangement. These cyclopropanes can be used to access complex bioactive scaffolds and serve as a platform for asymmetric cyclopropane synthesis.
Tim Köglmeier, Thomas J. Tiefel, Oliver Reiser   +2 more
wiley   +1 more source

Diastereoselectivity in the Staudinger reaction of pentafluorosulfanylaldimines and ketimines

Beilstein Journal of Organic Chemistry, 2013
β-Lactams were diastereoselectively formed by the reaction of SF5-containing aldimines, or an SF5-containing ketimine, with benzyloxyketene in a conrotatory ring closure process. Imine formation and cyclization were possible in spite of the acidification
Alexander Penger, Cortney N. von Hahmann, Alexander S. Filatov, John T. Welch   +3 more
doaj   +1 more source

TDAE Strategy for the Synthesis of 2,3-Diaryl N-Tosylaziridines

Molecules, 2013
We report herein an original and rapid synthesis of 2,3-diaryl N-tosylaziridines by TDAE strategy starting from ortho- or para-nitro(dichloromethyl)benzene derivatives and N-tosylimines. A mixture of cis/trans isomers was isolated from 1-(dichloromethyl)-
Thierry Terme, Cédric Spitz, Omar Khoumeri, Patrice Vanelle   +3 more
doaj   +1 more source

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

A speedy route to sterically encumbered, benzene-fused derivatives of privileged, naturally occurring hexahydropyrrolo[1,2-b]isoquinoline

Beilstein Journal of Organic Chemistry, 2017
A series of 15 benzene-fused hexahydropyrrolo[1,2-b]isoquinolonic acids with substantial degree of steric encumbrance has been prepared via a novel variant of the Castagnoli–Cushman reaction of homophthalic anhydride (HPA) and various indolenines.
Olga Bakulina, Alexander Ivanov, Vitalii Suslonov, Dmitry Dar’in, Mikhail Krasavin   +4 more
doaj   +1 more source

Synthesis of (–)-Bulgecinine and 5-epi-Bulgecinine through Proline-Catalysed Asymmetric α-Hydroxylation of an Aldehyde Derived from l-Glutamic Acid

SynOpen, 2019
A very efficient synthetic route to (–)-bulgecinine and 5-epibulgecinine from an aldehyde derived from l-glutamic acid is reported. Proline-catalysed asymmetric α-hydroxylation reaction of an aldehyde is the key step in this synthesis, which is used to ...
Vipin Kumar Jain, Mrityunjay Kumar
doaj   +1 more source