137134-54-4

Upstream product

• 76644-52-5 rac-3-acetoxycyclohexene 
• 108-59-8 malonic acid dimethyl ester 
• 105-53-3 diethyl malonate 
• 1521-51-3 rac-3-bromocyclohexene 
• 58329-99-0 cyclohex-2-enyl methyl carbonate 
• 996-82-7 sodium diethylmalonate 

Downstream Products

• 841251-12-5 (S)-diethyl 2-(2-propynyl)-2-(2-cyclohexyl)propane-1,3-dioate 

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.

Conformational Preferences of a Tropos Biphenyl Phosphinooxazoline-a Ligand with Wide Substrate Scope

Excellent enantioselectivities are observed in palladium-catalyzed allylic substitutions of a wide range of substrate types and nucleophiles using a bidentate ligand composed of oxazoline and chirally flexible biaryl phosphite elements. This unusually wid

Theoretical and Experimental Optimization of a New Amino Phosphite Ligand Library for Asymmetric Palladium-Catalyzed Allylic Substitution

A new library of modular amino phosphite ligands obtained in a few synthetic steps from enantiopure amino alcohols has been tested in asymmetric Pd-catalyzed allylic substitution. The modular ligand design is crucial to find highly selective catalysts for each substrate type using a wide range of C-, N-, and O-nucleophiles. A DFT study of the species responsible for the enantiocontrol was used to optimize the ligand structure. By selecting the ligand components, we were able to identify unprecedented catalytic systems that can create new chiral C-C, C-N, and C-O bonds in a variety of substrate types (hindered and unhindered) in high yields and enantioselectivities (ee values up to 99 %). Further studies on the Pd-π-allyl intermediates provided a deep understanding of the effect of ligand structure in the origin of enantioselectivity. Potential applications of the new Pd/amino phosphite catalysts were demonstrated by the practical synthesis of a range of chiral carbocycles by simple tandem reactions, with no loss of enantioselectivity.

Application of pyranoside phosphite-pyridine ligands to enantioselective metal-catalyzed allylic substitutions and conjugate 1,4-additions

A series of glucopyranoside phosphite-pyridine ligands have been applied in the metal-catalyzed allylic substitution and conjugate 1,4-addition reactions of several substrate types. We have been able to identify ligands that provided promising enantioselectivities in the Pd-catalyzed intermolecular allylic substitution of cyclic substrates (ee's up to 86%) and desymmetrization (ee's up to 94%) and in the Cu-catalyzed conjugate addition of challenging aliphatic enones (ee's up to 90%).

A new modular phosphite-pyridine ligand library for asymmetric Pd-catalyzed allylic substitution reactions: A study of the key Pd-π-allyl intermediates

A library of phosphite-pyridine ligands L1-L12 a-g has been successfully applied for the first time in the Pd-catalyzed allylic substitution reactions of several di- and trisubstituted substrates by using a wide range of C, N and O nucleophiles, among which are the little studied α-substituted malonates, β-diketones, and alkyl alcohols. The highly modular nature of this ligand library enables the substituents/configuration at the ligand backbone, and the substituents/configurations at the biaryl phosphite moiety to be easily and systematically varied. We found that the introduction of an enantiopure biaryl phosphite moiety played an essential role in increasing the versatility of the Pd-catalytic systems. Enantioselectivities were therefore high for several hindered and unhindered di- and trisubstituted substrates by using a wide range of C, N and O nucleophiles. Of particular note were the high enantioselectivities (up to>99 % ee) and high activities obtained for the trisubstituted substrates S6 and S7, which compare favorably with the best that have been reported in the literature. We have also extended the use of these new catalytic systems in alternative environmentally friendly solvents such as propylene carbonate and ionic liquids. Studies on the Pd-π-allyl intermediates provide a deeper understanding of the effect of ligand parameters on the origin of enantioselectivity. A library of phosphite-pyridine ligands has been successfully applied in the Pd-catalyzed allylic substitution reactions of several di- and trisubstituted substrates by using a wide range of C, N, and O nucleophiles. By carefully selecting the ligand components, high regio- and enantioselectivities (up to >99 % ee) and good activities have been achieved (see scheme). The NMR studies on the Pd-π-allyl intermediates provide a deeper understanding of the effect of ligand parameters on the origin of enantioselectivity. Copyright

Cycloisomerization of 1,6-enynes: Asymmetric multistep preparation of a hydrindane framework in water with polymeric catalysts

(Chemical Equation Presented) Cycloisomerization of 1,6-enynes proceeded smoothly in water under heterogeneous conditions in the presence of a palladium complex supported on polystyrene-poly(ethylene glycol) copolymer resin to give the corresponding cyclo

Synthesis of a novel type of chiral phosphinocarboxylic acids. The phosphine-palladium complexes catalyzed asymmetric allylic alkylation

A novel type of chiral cycloalkylphosphines bearing the carboxy group at the β-position were developed, and used for palladium catalyzed asymmetric allylic alkylation of allylic substrates such as 2-cyclohexenylacetate and 1,3-disubstituted-propenyl acetates (R1CH=CHCH(OAc)R2:R1=R2=Ph; R1=Ph, R2=(CH2)4OAc; R1=Ph, R2=(CH2)6OAc; R1=Ph, R2=(CH2)10OAc). Reaction of the propenyl acetates with soft carbon nucleophiles such as triethyl sodiophosphonoacetate and sodiomalonic acid esters in the presence of a palladium catalyst prepared in situ from Pd(OAc)2 and chiral (2-diphenylphospino)cycloalkanecarboxylic acids (7a,b) gave high yields of alkylation products (PhCH=CHCH(X)Ph: > 77%ee for X=CH(CO2Et)P(O)(OEt)2 and >72 %ee for X=CH(CO2Me)2. The alkylation products 15 and 28a-c were converted into optically active α-methylene-γ-lactone and α-methylene macrolide derivatives. The high stereoselectivity demonstrated by the chiral phosphinocarboxylic acid-palladium catalyzed allylic alkylation suggested to be caused by an electronic repulsion between the carboxy group on the ligand and the incoming soft carbon nucleophile, which directs the nucleophilic attack on one of the π-allyl carbons.