261506-10-9

Upstream product

• 693-03-8 n-butyl magnesium bromide 
• 2579-22-8 Phenylpropargyl aldehyde 
• 110-62-3 pentanal 
• 536-74-3 phenylacetylene 
• 72206-40-7 1-phenylhept-1-yn-3-ol 
• 591-50-4 iodobenzene 
• 51703-66-3 (S)-(-)-1-heptyn-3-ol 
• 72206-25-8 1-phenylhept-1-yn-3-one 

Downstream Products

• 20157-19-1 (S)-(E)-1-phenyl-hept-1-en-3-ol 

Relevant academic research and scientific papers

Ruthenium-Catalyzed Asymmetric Transfer Hydrogenation of Propargylic Ketones

The asymmetric transfer hydrogenation of α,β-propargyl ketones catalyzed by an in situ formed ruthenium-hydroxyamide complex was explored. The acetylenic alcohols were isolated in good to excellent yields with excellent ee values (typically >90 %) after s

Utilization of whole cell mediated deracemization in a chemoenzymatic synthesis of enantiomerically enriched polycyclic chromeno[4,3-b] pyrrolidines

Various aryl and alkyl substituted optically pure propargyl alcohols were obtained with excellent ee (up to >99%) and isolated yields (up to 87%) by deracemization using whole cells of Candida parapsilosis ATCC 7330. The whole cells show substrate specificity towards alkyl substituted propargyl alcohols and a switch in the enantioselectivity has been observed from 'R' to 'S' upon increasing the chain length. For the first time, enantiopure (R)-4-(3-hydroxybut-1-ynyl)benzonitrile, (R)-4-(biphenyl-4-yl)but-3-yn-2-ol, (S)-ethyl 3-hydroxy-5-phenylpent-4-ynoate and (S)-4-phenylbut-3-yne-1,2-diol were obtained using this strategy. Optically pure propargyl alcohol thus obtained was used as a chiral starting material in the synthesis of enantiomerically enriched poly-substituted pyrrolidines and a pyrrole derivative successfully demonstrating a chemoenzymatic route. This journal is

Catalytic asymmetric enyne addition to aldehdyes and Rh(I)-catalyzed stereoselective domino Pauson-Khand/[4 + 2] cycloaddition

The 1,1′-bi-2-naphthol-ZnEt2-Ti(OiPr) 4-Cy2NH system is found to catalyze the 1,3-enyne addition to aliphatic aldehydes as well as other aldehydes at room temperature with 75-96% yield and 82-97% ee. This system is also broadly applicable for the highly enantioselective reaction of other alkyl-, aryl-, and silylalkynes with structurally diverse aldehydes. The propargylic alcohols prepared from the catalytic asymmetric enyne addition to aliphatic aldehydes are used to prepare a series of optically active trienynes. In the presence of a catalytic amount of [RhCl(CO)2]2 and 1 atm of CO, the optically active trienynes undergo highly stereoselective domino Pauson-Khand/[4 + 2] cycloaddition to generate optically active multicyclic products. The Rh(I) catalyst is also found to catalyze the coupling of a diyne with CO followed by [4 + 2] cycloaddition to generate an optically active multicyclic product. These transformations are potentially useful for the asymmetric synthesis of polyquinanes containing a quaternary chiral carbon center.

Catalytic asymmetric synthesis of chiral propargylic alcohols for the intramolecular Pauson-Khand cycloaddition

Several methods for the catalytic asymmetric alkyne addition to aldehydes are used to prepare the propargylic alcohol-based chiral en-ynes. Protection of the propargylic alcohols with either an acetyl or a methyl group allows the resulting en-ynes to undergo the intramolecular Pauson-Khand reaction to form the corresponding optically active 5,5- and 5,6-fused bicyclic products with high diastereoselectivity and high enantiomeric purity. In the major product, the propargylic substituent and the bridgehead hydrogen are cis with respect to each other on the fused bicyclic rings. The enantiomeric purity of the propargylic alcohols generated from the asymmetric alkyne addition is maintained in the cycloaddition products. The allylic ethers of the chiral propargylic alcohols are prepared which can also undergo the highly diastereoselective Pauson-Khand cycloaddition with retention of the high enantiomeric purity. This study has shown that the size of the substituents at the propargylic position as well as on the alkyne is important for the diastereoselectivity with the greater bulkiness of the substituents giving higher diastereoselectivity.

Palladium-catalyzed γ-selective and stereospecific allyl-aryl coupling between acyclic allylic esters and arylboronic acids

Reactions between acyclic (E)-allylic acetates and arylboronic acids in the presence of a palladium catalyst prepared from Pd(OAc)2, phenanthroline (or bipyridine), and AgSbF6 (1:1.2:1) proceeded with excellent γ-selectivity to afford allyl-aryl coupling products with E-configuration. The reactions of α-chiral allylic acetates took place with excellent α-to-γ chirality transfer with syn stereochemistry to give allylated arenes with a stereogenic center at the benzylic position. The reaction tolerated a broad range of functional groups in both the allylic acetates and the arylboronic acids. Furthermore, γ-arylation of cinnamyl alcohol derivatives afforded gem-diarylalkane derivatives containing an unconjugated alkenic substituent. The synthetic utility of this method was demonstrated by its utilization in an efficient synthesis of (+)-sertraline, an antidepressant agent. The observed γ-regioselectivity and E-1,3-syn stereochemistry were rationalized based on a Pd(II) mechanism involving transmetalation between a cationic mono(acyloxo)palladium(II) complex and arylboronic acid, and directed carbopalladation followed by syn-β-acyloxy elimination. The results of stoichiometric reactions of palladium complexes related to possible intermediates were fully consistent with the proposed mechanism.

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.

Synthesis of new Schiff base-camphorsulfonyl amide ligands and in situ screening in the asymmetric additions of organozinc reagents to aldehydes

We have designed and synthesized a new library of highly modular Schiff base-camphorsulfonyl amide ligands from readily available starting materials. These ligands have been used in the asymmetric addition of diethyl zinc to aldehydes in good yields (up to 91%) and high enantioselectivities (up to 93%). Moreover, when the ligands were used in the asymmetric addition of phenylacetylene to aldehydes, good yields and moderate to high ee values (up to 90%) were obtained. The introduction of the camphorsulfonyl moiety into the ligands is highly critical for the selectivities of the reactions.

Cationic rhodium(I)/bisphosphane complex-catalyzed isomerization of secondary propargylic alcohols to α,β-enones

We have determined that hydrogenated cationic Rh(I)/bisphosphane complexes are highly active catalysts for the isomerization of secondary propargylic alcohols to α,β-enones. A kinetic resolution of secondary propargylic alcohols proceeded with moderate selectivity with [Rh((R)-BINA-P)]OTf as a catalyst. Mechanistic studies revealed that the isomerization proceeds through intramolecular 1,3- and 1,2-hydrogen migration pathways. The isomerization of propargylic diol derivatives was also investigated, which revealed that 1,4-diketones, furans, and α,β-enones were obtained from 2-butyn-1,4-diol, 1-methoxy-2-butyn-4-ol, and 1-acetoxy-2-butyn-4-ol derivatives, respectively. Furthermore, chemoselectivity of the isomerization of an acetylenic diol was investigated, and preferential oxidation of a propargylic hydroxy group was observed. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.

Chiral macrocycle-catalyzed highly enantioselective phenylacetylene addition to aliphatic and vinyl aldehydes

(Chemical Equation Presented) The 1,1′-binaphthyl macrocycle (S)-2 is found to be an excellent catalyst for the alkyne addition to aldehydes. In the presence of (S)-2 (20 mol %) and Me2Zn (2 equiv) in THF at room temperature, the addition of ph

Cationic rhodium(I)/BINAP complex-catalyzed isomerization of secondary propargylic alcohols to α,β-enones

(Chemical Equation Presented) We have developed a cationic rhodium(I)/BINAP complex-catalyzed isomerization of secondary propargylic alcohols to α,β-enones. The asymmetric variant of this reaction, a kinetic resolution of secondary propargylic alcohols, was also developed with good selectivity. The mechanistic study revealed that the isomerization proceeds through intramolecular 1,3- and 1,2-hydrogen migration pathways.