90361-56-1Relevant articles and documents
Stereoselective Construction of γ-Lactams via Copper-Catalyzed Borylacylation
Bajohr, Jonathan,Lautens, Mark,Polishchuk, Iuliia,Torelli, Alexa,Whyte, Andrew
supporting information, p. 7915 - 7919 (2020/11/02)
A versatile and highly stereoselective borylative cyclization to generate polyfunctionalized γ-lactams has been developed. The stereoselective synthesis of these key ring systems is crucial due to their ubiquity in natural products. We report the diastero- and enantioselective construction of di- and trisubstituted γ-lactam cores, with examples containing an enantioenriched quaternary carbon.
Zn-Catalyzed Enantio- and Diastereoselective Formal [4 + 2] Cycloaddition Involving Two Electron-Deficient Partners: Asymmetric Synthesis of Piperidines from 1-Azadienes and Nitro-Alkenes
Chu, John C. K.,Dalton, Derek M.,Rovis, Tomislav
supporting information, p. 4445 - 4452 (2015/04/14)
We report a catalytic asymmetric synthesis of piperidines through [4 + 2] cycloaddition of 1-azadienes and nitro-alkenes. The reaction uses earth abundant Zn as catalyst and is highly diastereo- and regioselective. A novel BOPA ligand (F-BOPA) confers high reactivity and enantioselectivity in the process. The presence of ortho substitution on the arenes adjacent to the bis(oxazolines) was found to be particularly impactful, due to limiting the undesired coordination of 1-azadiene to the Lewis acid and thus allowing the reaction to be carried out at lower temperature. A series of secondary kinetic isotope effect studies using a range of ligands implicates a stepwise mechanism for the transformation, involving an initial Michael-type addition of the imine to the nitro-alkene followed by a cyclization event. The stepwise mechanism obviates the electronic requirement inherent to a concerted mechanism, explaining the successful cycloaddition between two electron-deficient partners. (Chemical Equation Presented).
Anti-tumor compounds, pharmaceutical compositions, methods for preparation thereof and for treatment
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, (2008/06/13)
The present invention is directed to novel taxanes useful as chemotherapeutic agents or their precursors. Processes for preparing the novel taxanes include coupling reactions, in the presence of a base, of baccatin of formula (III) or (IV) STR1 with β-lac