73952-47-3

Upstream product

• 401614-23-1 2-((S)-1-Phenyl-prop-2-ynyloxy)-tetrahydro-pyran 
• 4187-87-5 (R)-1-phenyl-2-propyn-1-ol 
• 100-52-7 benzaldehyde 
• 623-47-2 propynoic acid ethyl ester 
• 557-20-0 diethylzinc 
• 54966-47-1 4-oxo-4-phenyl-but-2-ynoic acid ethyl ester 

Downstream Products

• 943435-58-3 (R)-methyl 4-hydroxy-4-phenylbut-2-ynoate 

Relevant academic research and scientific papers

Ruthenium-catalyzed [2 + 2] cycloadditions between norbornene and propargylic alcohols or their derivatives

Diastereoselective ruthenium-catalyzed [2 + 2] cycloadditions of norbornene and propargylic alcohols or their derivatives were investigated. The cycloadditions were found to be highly stereoselective, giving exo cycloadducts in moderate to excellent yields with diastereoselectivities up to 92:8. When a chiral propargylic alcohol was used in the cycloaddition, up to 80% ee of the [2 + 2] cycloadducts was observed after oxidation of the alcohol.

Asymmetric alkynylation of aldehydes with propiolates without high reagent loading and any additives

The asymmetric alkynylation of aliphatic and aromatic aldehydes with propiolates was mediated by dialkylzinc and a novel prolinol catalyst without high reagent loading and any additives, such as Ti(Oi-Pr)4, to give the corresponding γ-hydroxy-α,β-acetylenic esters with high enantiomeric excess of up to 95%.

Asymmetric synthesis of γ-hydroxy-α,β-acetylenic esters catalyzed by oxazolidine-titanium complex

An efficient catalytic system has been developed for the enantioselective reaction of alkynoates with aromatic aldehydes for the synthesis of optically active γ-hydroxy-α,β-acetylenic esters (with up to 81% isolated yield and up to 84% enantioselectivity)

3,3′-anisyl-substituted BINOL, H4BINOL, and H 8BINOL ligands: Asymmetric synthesis of diverse propargylic alcohols and their ring-closing metathesis to chiral cycloalkenes

(Chemical Equation Presented) A series of optically active BINOL, H 4BINOL, and H8BINOL derivatives were prepared. These compounds in combination with ZnEt2 and Ti(OiPr) 4 were used to catalyze the asymmetric reaction of alkynes with aldehydes to generate chiral propargylic alcohols at room temperature. Through this comparative study, a 3,3′-bisanisyl-substituted H8BINOL (S)-7 was found to be a generally enantioselective catalyst for the reaction of structurally diverse terminal alkynes with a variety of aldehydes. It catalyzed the reactions of alkyl propiolates with 88-99% ee; the reactions of phenylacetylene with 81-87% ee; the reactions of 4-phenyl-1-butyne, an alkyl alkyne, with 77-89% ee; and the reactions of trimethylsilylacetylene with 92-97% ee. The optically active propargylic alcohols generated from this catalytic asymmetric alkyne addition were observed to undergo efficient ring-closing-metathesis (RCM) reaction in the presence of the Grubbs II catalyst to produce chiral cycloalkenes. It was further found that some of the chiral propargylic alcohols underwent a highly chemoselective tandem RCM hydrogenation reaction with retention of the enantiomeric purity. 2009 American Chemical Society.

ASYMMETRIC REDUCTIONS OF PROPARGYL KETONESAN EFFECTIVE APPROACH TO THE SYNTHESIS OF OPTICALLY-ACTIVE COMPOUNDS

Propargyl ketones are readily reduced by the asymmetric reducing agent B-3-pinanyl-9-borabicyclo-nonane (Alpine-borane).The reagent prepared from (+)-α-pinene and 9-BBN provides the R enantiomer while the S enantiomer can be obtained from (-)-α-pinene.Alternatively the S enantiomer ca be prepared from the reagent derived from 9-BBn and the benzyl ether of nopol (6,6-dimethyl-bicyclohept-2-ene-2-ethanol).The limiting factor in obtaining high enantiomeric induction is often the enantiomeric purity of the α-pinene.With 100percent enantiomerically pure α-pinene, propargyl alcohols of essentially 100percent ee can be obtained.A predictive rationalization of the transition state leading to this remarkable selection is presented.The acetylene unit of the propargyl alcohol provides a convenient handle for transformations to other useful, optically-active products.The use of propargyl alcohols for the synthesis of optically-active α- and β-substituted γ-lactones, and δ-lactones is illustrated.