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• 58329-99-0 cyclohex-2-enyl methyl carbonate 
• 14429-02-8 benzyl-(4-methoxybenzyl)amine 
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Relevant academic research and scientific papers

Carbamate-based P,O-ligands for asymmetric allylic alkylations

Herein we report the design and successful catalytic application of modified Trost-ligands in asymmetric allylic alkylation (AAA) reactions. A small set of carbamate-monophosphine P,O-ligands has been prepared in a straightforward two-step synthetic procedure. After optimization of the reaction conditions, high catalytic activities and excellent enantioselectivity up to >99% have been attained.

An improved class of phosphite-oxazoline ligands for Pd-catalyzed allylic substitution reactions

A method for generation of Pd/phosphite-oxazoline catalysts containing an alkyl backbone chain has been successfully applied to Pd-catalyzed allylic substitution reactions. By carefully selecting the substituents at both the alkyl backbone chain and the oxazoline of the ligand, as well as the configuration of the biaryl phosphite group, high activities (TOF > 8000 mol substrate × (mol Pd × h)?1) and excellent enantioselectivities (ee's up to 99%) have been achieved for many hindered and unhindered substrates with a wide range of C-, O-, and N-nucleophiles (73 substitution products in total). Moreover, DFT and NMR studies of the key Pd-allyl complexes allowed us to better understand the origin of the excellent enantioselectivities observed experimentally. The useful application of the Pd/phosphite-oxazoline catalysts was demonstrated by the syntheses of many chiral carbobicycles, with multiples stereocenters, by simple sequential reactions involving Pd-allylic substitution and either 1,6-enyne cyclization or Pauson?Khand enyne cyclization.

Lithium Chloride Catalyzed Asymmetric Domino Aza-Michael Addition/[3 + 2] Cycloaddition Reactions for the Synthesis of Spiro- and Bicyclic α,β,γ-Triamino Acid Derivatives

Angularly and peri-fused tricyclic pyrrolidinopyrazolines are efficiently prepared by LiCl-catalyzed domino aza-Michael addition-1,3-dipolar cycloaddition reactions. The absolute stereochemistry is controlled in the aza-Michael addition step, nonaflyl azide serves as effective diazo transfer reagent to the formed enolate and the resulting diazo dipole engages in the 1,3-dipolar cycloaddition step. The resulting tricyclic pyrrolidinopyrazolines can be easily transformed to enantiomerically enriched nonproteinogenic spirocyclic α,β,γ-triamino acids, angularly or peri-fused tricyclic β-prolines or pyrimidines. The activity of the tricyclic amino acid derivatives against the hepatitis C virus was determined.

Cofactor-Controlled Chirality of Tropoisomeric Ligand

A new tropos ligand with an integrated anion receptor site has been prepared. Chiral carboxylate and phosphate anions that bind in the anion receptor unit proved capable of stabilizing chiral conformations of the achiral flexible bidentate biaryl phosphite ligand, as shown by variable temperature 1H and 31P NMR spectroscopical studies of palladium(0) olefin complexes. Palladium allyl complexes of the supramolecular ligand-chiral cofactor assemblies catalyzed asymmetric allylic substitutions of rac-(E)-1,3-diphenyl-2-propenyl carbonate and rac-3-cyclohexenyl carbonate with malonate and benzylamine as nucleophiles to provide nonracemic products. Although moderate enantioselectivities were observed, (ee:s up to 66%), the results confirm the ability of the anionic guests to affect the conformation of the ligand.

Asymmetric catalyzed allylic substitution using a Pd/P-S catalyst library with exceptional high substrate and nucleophile versatility: DFT and Pd-π-allyl key intermediates studies

A large library of furanoside phosphite/phosphinite/phosphine-thioether ligands L1-L17a-l has been applied in the Pd-catalyzed allylic substitution reactions of several substrate types using a wide range of nucleophiles. These ligands, which are prepared from inexpensive d-xylose, also incorporate the advantages of the heterodonor, the robustness of the thioether moiety, and the extra control provided by the flexibility of the chiral pocket through the presence of a biaryl phosphite group and a modular sugar backbone. By selecting the ligand components, we have been able to identify catalytic systems that can create new C-C, C-N, and C-O bonds in several substrate types (hindered and unhindered) using a wide range of nucleophiles in high yields and enantioselectivities (ee's up to >99%). Of particular note are the excellent enantioselectivities obtained in the etherification of linear and cyclic substrates, which represent the first example of successful etherification of both substrate types. The DFT computational study is in agreement with an early transition state. Further studies on the Pd-π-allyl intermediates provided a deep understanding of the effect of ligand structure in the origin of enantioselectivity.

Pd-catalyzed asymmetric allylic amination using easily accessible metallocenyl P,N-ligands

Compared to their C1-symmetric counterparts, planar chiral C2-symmetric metallocenyl P,N-ligands are efficient chiral ligands for Pd-catalyzed asymmetric allylic aminations, providing a number of amination products with high enantios

Highly versatile Pd-thioether-phosphite catalytic systems for asymmetric allylic alkylation, amination, and etherification reactions

A Pd-furanoside thioether-phosphite catalytic system that can create new C-C, C-N, and C-O bonds in several substrate types using a wide range of nucleophiles in high yields and enantioselectivities has been identified. Of particular note are the excellent enantioselectivities obtained in the etherification of linear and cyclic substrates. The potential application of the new Pd-thioether-phosphite catalytic systems was also demonstrated by the synthesis of the chiral carbo- and heterocycles.

Towards continuous flow, highly enantioselective allylic animation: ligand design, optimization and supporting

A family of enantiopure diphenylphosphinooxazolines (PHOX) containing in their structures a sterically tunable alkoxymethyl group (-CH2OR) has been optimized for the palladium-catalyzed asymmetric allylic amination. The optimal catalyst (R=CH3), depicting very high catalytic activity and broad scope applicability, has been further modified to include an ω-alkynyloxy substituent of variable length for polymer supporting via click chemistry, and has been anchored onto slightly cross-linked azidomethyl poly(styrene). The length of a polymethylene chain connecting the PHOX unit with the 1,2,3-triazole linker has been optimized, and the first polymer-supported PHOX ligands for the highly enantioselective allylic amination have been prepared in this manner. Conditions for catalyst recovery and reuse in microwave-promoted amination reactions have been established, and the system has been finally adapted to continuous flow operation.

Phosphine containing oligonucleotides for the development of metallodeoxyribozymes

Novel transition metal catalysts based on oligonucleotides can be easily obtained by functionalization of 5-iodouridine with phosphine ligands, resulting in good asymmetric induction in palladium catalyzed allylic nucleophilic substitution. The Royal Society of Chemistry.

Novel C2-symmetric planar chiral diphosphine ligands and their application in Pd-catalyzed asymmetric allylic substitutions

(Chemical Equation Presented) Novel C2-symmetric diphosphine ligands possessing only the planar chirality of ruthenocene, 1,1′-bis(diphenylphosphino)-2,2′-disubstituted-ruthenocenes (4), were prepared. With this kind of ligands, excellent enant