98831-01-7

Upstream product

• 585-07-9 tert-Butyl methacrylate 
• 960-16-7 tributylphenylstannane 
• 108-86-1 bromobenzene 
• 591-50-4 iodobenzene 
• 22946-43-6 (E)-methyl-2-methyl-3-phenylacrylate 
• 865-47-4 potassium tert-butylate 
• 26735-95-5 2-methyl-3-hydroxy-3-phenylpropionic acid t-butyl ester 
• 20487-40-5 tert-butyl propionate 
• 56904-86-0 tert-butyl 2-(triphenylphosphoranylidene)propionate 
• 100-51-6 benzyl alcohol 
• 39149-80-9 tert-butyl 2-bromopropionate 
• 849240-08-0 (1-tert-butoxycarbonyl-ethyl)-triphenyl-phosphonium; bromide 
• 98830-92-3 tert-butyl α-(tri-n-butylstannyl)cinnamate 
• 74-88-4 methyl iodide 

Downstream Products

• 151214-60-7 tert-butyl (2S,3S,αR)-3-(N-benzyl-N-α-methylbenzylamino)-2-methyl-3-phenylpropionate 
• 70836-95-2 methyl-3-phenyl-propionic acid tert-butyl ester 
• 700800-36-8 (S,S)-α-methyl-β-phenylalanine 
• 151133-04-9 tert-butyl (2S,3S)-3-amino-2-methyl-3-phenylpropanoate 
• 99261-03-7 (2S,3R)-2-Methyl-4,4-bis-methylsulfanyl-3-phenyl-4-trimethylsilanyl-butyric acid tert-butyl ester 
• 99261-03-7 (2R,3R)-2-Methyl-4,4-bis-methylsulfanyl-3-phenyl-4-trimethylsilanyl-butyric acid tert-butyl ester 

Relevant academic research and scientific papers

Construction of acyclic all-carbon quaternary stereocenter based on asymmetric michael addition of chiral amine

Acyclic asymmetric quaternary stereocenters, which are composed of four carbon-carbon bonds, were finely constructed by utilizing a face-selective alkylation of enolate intermediates derived from an asymmetric Michael addition reaction of a chiral lithium amide with trisubstituted (E)-α,β-unsaturated esters. The present face-selective alkylation was able to employ diverse alkyl halides as an electrophile to afford various Michael adducts having an all-carbon quaternary stereocenter. With regard to the deprotection of the chiral auxiliary, N-iodosuccinimide used in our previous study did not work in the present cases; however, we found that pyridine iodine monochloride in the presence of H2O was effective to remove the bornyl group and the benzyl group on the amino group to provide the β-amino ester derivative.

Selective Construction of C?C and C=C Bonds by Manganese Catalyzed Coupling of Alcohols with Phosphorus Ylides

Herein, we report the manganese catalyzed coupling of alcohols with phosphorus ylides. The selectivity in the coupling of primary alcohols with phosphorus ylides to form carbon-carbon single (C?C) and carbon-carbon double (C=C) bonds can be controlled by the ligands. In the conversion of more challenging secondary alcohols with phosphorus ylides the selectivity towards the formation of C?C vs. C=C bonds can be controlled by the reaction conditions, namely the amount of base. The scope and limitations of the coupling reactions were thoroughly evaluated by the conversion of 21 alcohols and 15 ylides. Notably, compared to existing methods, which are based on precious metal complexes as catalysts, the present catalytic system is based on earth abundant manganese catalysts. The reaction can also be performed in a sequential one-pot reaction generating the phosphorus ylide in situ followed manganese catalyzed C?C and C=C bond formation. Mechanistic studies suggest that the C?C bond was generated via a borrowing hydrogen pathway and the C=C bond formation followed an acceptorless dehydrogenative coupling pathway. (Figure presented.).

A facile and convenient synthesis of trisubstituted (E)-α,β-unsaturated esters by tandem acetylation-E1CB reaction

A facile and convenient synthesis of trisubstituted (E)-α,β-unsaturated esters was developed by improving our previously established method. The new method circumvented the separation of the intermediates, which have an activating group of the hydroxyl group in β-hydroxy esters, furnishing α,β-unsaturated esters in shorter steps than the previous method: an acetylation of β-hydroxy group and subsequent E1cB reaction proceeded in tandem. In addition, the new method can not only employ a diastereomeric mixture of the substrate for the E1cB reaction, it has a wide substrate scope as well, which would enable the synthesis of various trisubstituted (E)-α,β-unsaturated esters.

Copper-catalyzed diastereoselective synthesis of β-boryl-α-quaternary carbon carboxylic esters

Cu(i)-Catalyzed diastereoselective carboboration of α-alkyl-substituted α,β-unsaturated carboxylic esters to produce β-boryl-α-quaternary carbon esters was developed. The carbon skeletons of dialkyl sulfates, primary allyl halides, and benzyl bromides were transferred to the α-position of the substrates to provide products in moderate to good yields with a diastereoselectivity of >95% in most cases. Substrates bearing a β-(hetero)aryl substituent gave higher diastereoselectivities than those bearing a linear β-alkyl substituent. The crystal structure of the potassium trifluoroborate derivative shows that the reactions probably go through a copper(i) enolate intermediate and the diastereoselectivity arises from the electrophilic attack of electrophiles to the less hindered side of the enolates.

Novel and practical asymmetric synthesis of β2,3-amino esters using asymmetric Michael addition of chiral amine

A practical method for the synthesis of chiral β2,3-amino esters having various substituents was developed, which is characterized by an asymmetric Michael addition reaction of a chiral lithium amide with trisubstituted (E)-α,β-unsaturated esters. We found that a highly face-selective protonation occurred by the quick addition of water to the enolate intermediate derived from the Michael addition reaction to afford N-protected β2,3-amino esters in moderate to excellent yields. This finding was made possible by the facile preparation of geometrically pure trisubstituted (E)-α,β-unsaturated esters, which was established recently by our group. The subsequent deprotection of the amino group in the Michael adduct by using N-iodosuccinimide (NIS) efficiently provided β2,3-amino esters having various substituents.

Investigation of sol-gel supported palladium catalysts for Heck coupling reactions in o/w-microemulsions

Sol-gel supported palladium catalysts are investigated for the Heck coupling reaction between styrene and iodo-/bromobenzene to trans-stilbenes in o/w-microemulsions as alternative reaction medium. High conversions and selectivities are obtained with these catalysts and they show better catalytic performance than their commercial analogs Pd@SiO2 or Pd/C. The influence of the catalyst structure on the activity is investigated in detail showing mass transport limitations that can be optimized by the palladium loading. The catalyst is recyclable >6 times with negligible palladium leaching into the solution. Because of the good recyclability under retention of activity and selectivity, the influence of transport limitations is suppressed and the total catalyst efficiency is increased to more than 2.

Iron(II)-catalyzed asymmetric epoxidation of trisubstituted α,β-unsaturated esters

The asymmetric epoxidation of trisubstituted α,β-unsaturated esters was developed. The oxidation utilizes a pseudo-C2-symmetric iron(II) catalyst [Fe(L)2(CH3CN)(OTf)](OTf) (Tf = trifluoromethylsulfonyl) and pera

Oxidative palladium(II) catalysis: A highly efficient and chemoselective cross-coupling method for carbon-carbon bond formation under base-free and nitrogenous-ligand conditions

We report herein the development of a general and mild protocol of oxygen-promoted Pd(II) catalysis resulting in the selective cross-couplings of alkenyl- and arylboron compounds with various olefins. Unlike most cross-coupling reactions, this new methodology works well even in the absence of bases, consequently averting undesired homo-couplings. Nitrogen-based ligands including dimethyl-phenanathroline enhance reactivities and offer a highly efficient and stereoselective methodology to overcome challenging substrate limitations. For instance, oxidative palladium(II) catalysis is effective with highly substituted alkenes and cyclic alkenes, which are known to be incompatible with other known catalytic conditions. Most examined reactions progressed smoothly to completion at low temperatures and in short times. These interesting results provide mechanistic insights and utilities for a new paradigm of palladium catalytic cycles without bases.

Mild and efficient aryl-alkenyl coupling via Pd(II) catalysis in the presence of oxygen or Cu(II) oxidants

We report herein a mild and efficient method for carbon-carbon bond formation between aryl stannanes and olefins via Pd(II) catalysis in the presence of oxygen or Cu(II) oxidants as a reoxidant. The process allows reactions between various olefins and aryl stannanes of varying electron density. Coupling methods under these oxidation conditions are comparatively described, and the benefits and limitations are also discussed.

SYNTHETIC UTILITY OF α-STANNYL α,β-UNSATURATED ESTERS AS REAGENTS FOR β-SUBSTITUTED ACRYLATE α-ANION SYNTHONS: TIN-LITHIUM EXCHANGE AND PALLADIUM-CATALIZED COUPLING REACTIONS

The tin-lithium exchange and the palladium-catalized coupling reactions of the title compounds have been studied.The latter reaction was found to be more efficient for functionalizing the α-carbon of these esters.