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Upstream product

• 86659-03-2 ((E)-4,4-Diethoxy-buta-1,3-dienyl)-benzene 
• 64-17-5 ethanol 
• 129029-61-4 2-hydroxy-4-phenylbut-3-enoic acid 
• 117306-12-4 (2R,3E)-2-hydroxy-4-phenyl-3-butenenitrile 
• 14371-10-9 (E)-3-phenylpropenal 
• 924-44-7 glyoxylic acid ethyl ester 
• 19372-00-0 1-(trimethylsilyl)-2-phenylethene 
• 6783-05-7 trans-2-phenylvinylboronic acid 
• 1914-59-6 (E)-2-oxo-4-phenyl-3-butenoic acid 
• 17451-20-6 (E)-ethyl-2-oxo-4-phenylbut-3-enoate 

Relevant academic research and scientific papers

Synthesis of Enantioenriched γ-Amino-α,β-unsaturated Esters Utilizing Palladium-Catalyzed Rearrangement of Allylic Carbamates for Direct Application to Formal [3 + 2] Cycloaddition

An efficient synthesis of enantioenriched γ-amino-α,β-unsaturated esters was developed by utilizing the palladium-catalyzed decarboxylative rearrangement of enantioenriched allylic carbamates possessing an ester moiety at the allylic position. The reaction proceeded in good yield with a high degree of chirality transfer by making use of Xantphos as a superior ligand for the catalyst. The products directly participated in the formal [3 + 2] cycloaddition reaction with tosyl isocyanate under Br?nsted base catalysis to afford enantioenriched β,γ-diamino acid derived imidazolidin-2-ones as versatile chiral building blocks.

Regio- and Stereospecific C- and O-Allylation of Phenols via φ-Allyl Pd Complexes Derived from Allylic Ester Carbonates

Two complementary strategies have been developed for the C- and O-allylation of phenols via a common φ-allyl Pd complex. While O-allylation of phenols by this method is a well-recognized reaction of general utility, the associated para-selective C-allylation reaction is still in its infancy. Cationic φ-allyl Pd intermediates, derived from allylic ester carbonates and palladium(0) catalyst, were found to undergo the Friedel-Crafts-type para-selective C-allylations with nine different phenols. Both C- and O-allylated products were obtained in good to excellent yields following a metal-catalyzed regio- and stereospecific substitutive 1,3-transposition. Conditions were also identified that control access to either allylated product. Finally, a study of the equilibrium established between the two allylation products revealed that the O-allylated compound was the kinetic product and the C-allylated compound the thermodynamic product.

Cobalt-Catalyzed Enantioselective Vinylation of Activated Ketones and Imines

We present here an unprecedented cobalt-catalyzed enantioselective vinylation of α-ketoesters, isatins, and imines to deliver a range of synthetically useful allylic alcohols and amines in high enantiopurity. This method employs commercially available and easy to handle catalysts and reagents and exhibits a high degree of practicality. The efficiency, selectivity, and operational simplicity of this catalytic system coupled with the substrate generality render this method a valuable tool in organic synthesis.

Direct asymmetric hydrogenation of 2-oxo-4-arylbut-3-enoic acids

A challenging direct asymmetric hydrogenation of (E)-2-oxo-4-arylbut-3- enoic acids to give 2-hydroxy-4-arylbutanoic acids (85.4-91.8% ee) was achieved with a Ru catalyst based on SunPhos as the chiral ligand. Further investigation of the reaction revealed that partial isomerization of 2-hydroxy-4-arylbutenoic acids was involved in the hydrogenation process. Employing the reaction conditions to the hydrogenation of 2-oxo-4-phenylbutanoic acid resulted in better enantioselectivity (91.8% ee) and efficiency (TON = 2000, TOF = 200 h-1), which offers a useful method for the synthesis of a common intermediate for ACE inhibitors.

Asymmetric nucleophilic acylation of aldehydes via 1,1-heterodisubstituted alkenes

Aldehydes are asymmetrically acylated by a two step sequence that is initiated by a homologation step to 1,1-heterodisubstituted alkenes followed by asymmetric dihydroxylation. Thus, ketene O,S-acetals are efficiently prepared from aldehydes by a Peterson olefination with lithiated methoxy-phenylthiotrimethylsilyl methane 14 as the C-1 source. Although they are dihydroxylated with the Sharpless catalyst with moderate to good enantioselectivity (62-80% ee), the process is not efficient owing to the low chemical yields of the desired α-hydroxy methyl esters (7-37%). Use of the corresponding sulfoxide 24 or sulfon 25 led to an improved chemical yield of α-hydroxy methyl ester 19, but the stereoselectivity was diminished. In contrast, intermediate ketene O,O-acetals are prepared by a Horner-Wittig reaction with phosphine oxide 31 and are dihydroxylated both with good chemical and stereochemical yield. The concept is applicable to aromatic, aliphatic, and chiral aldehydes. For example, this short sequence allows exclusive and independent preparation of both diastereomeric heptoses 69 a and 69 b.

STEREOSELECTIVE REDUCTION OF C=X BY A CHIRAL 1,4-DIHYDROPYRIDINE (NADH-MIMIC) IN A SELF-IMMOLATIVE PROCESS

A series of prochiral ketones and a prochiral imine was reduced with high absolute stereoselectivity using an optically active 4-methyl-1,4-dihydropyridine in the presence of Mg(ClO4)2.