372021-72-2

Upstream product

• 75-77-4 chloro-trimethyl-silane 
• 4784-77-4 (E/Z)-crotyl bromide 
• 123-11-5 4-methoxy-benzaldehyde 
• 18147-55-2 (Z)-crotyltrichlorosilane 
• 4784-77-4 (E)-1-Bromo-2-butene 
• 590-18-1 (Z)-2-Butene 
• 1357478-15-9 (±)-2-(but-3-en-2-yl)-5,5-dimethyl-1,3,2-dioxaborinane 
• 18147-55-2 (E)-crotyltrichlorosilane 
• 18147-55-2 but-2-enyltrichlorosilane 

Relevant academic research and scientific papers

Application of tridentate bis(oxazoline) ligands in catalytic asymmetric Nozaki-Hiyama allylation and crotylation: An example of high enantioselection with a non-symmetric bis(oxazoline) ligand

A series of both symmetric and non-symmetric bis(oxazoline) ligands was applied in the Nozaki-Hiyama allylation and crotylation of benzaldehyde. It was found that both the magnitude and sense of the asymmetric induction depended strongly on the nature and

Engaging Aldehydes in CuH-Catalyzed Reductive Coupling Reactions: Stereoselective Allylation with Unactivated 1,3-Diene Pronucleophiles

Recently, CuH-catalyzed reductive coupling processes involving carbonyl compounds and imines have become attractive alternatives to traditional methods for stereoselective addition because of their ability to use readily accessible and stable olefins as surrogates for organometallic nucleophiles. However, the inability to use aldehydes, which usually reduce too rapidly in the presence of copper hydride complexes to be viable substrates, has been a major limitation. Shown here is that by exploiting relative concentration effects through kinetic control, this intrinsic reactivity can be inverted and the reductive coupling of 1,3-dienes with aldehydes achieved. Using this method, both aromatic and aliphatic aldehydes can be transformed into synthetically valuable homoallylic alcohols with high levels of diastereo- and enantioselectivities, and in the presence of many useful functional groups. Furthermore, using a combination of theoretical (DFT) and experimental methods, important mechanistic features of this reaction related to stereo- and chemoselectivities were uncovered.

Allylation reactions of aldehydes with allylboronates in aqueous media: Unique reactivity and selectivity that are only observed in the presence of water

Zn(OH)2-catalyzed allylation reactions of aldehydes with allylboronates in aqueous media have been developed. In contrast to conventional allylboration reactions of aldehydes in organic solvents, the α-addition products were obtained exclusively. A catalytic cycle in which the allylzinc species was generated through a B-to-Zn exchange process is proposed and kinetic studies were performed. The key intermediate, an allylzinc species, was detected by HRMS (ESI) analysis and by online continuous MS (ESI) analysis. This analysis revealed that, in aqueous media, the allylzinc species competitively reacted with the aldehydes and water. An investigation of the reactivity and selectivity of the allylzinc species by using several typical allylboronates (6a, 6b, 6c, 6d) clarified several important roles of water in this allylation reaction. The allylation reactions of aldehydes with allylboronic acid 2,2-dimethyl-1,3-propanediol esters proceeded smoothly in the presence of catalytic amounts of Zn(OH)2 and achiral ligand 4d in aqueous media to afford the corresponding syn-adducts in high yields with high diastereoselectivities. In all cases, the α-addition products were obtained and a wide substrate scope was tolerated. Furthermore, this reaction was applied to asymmetric catalysis by using chiral ligand 9. Based on the X-ray structure of the Zn-9 complex, several nonsymmetrical chiral ligands were also found to be effective. This reaction was further applied to catalytic asymmetric alkylallylation, chloroallylation, and alkoxyallylation processes and the synthetic utility of these reactions has been demonstrated. Still waters run deep: The Zn(OH)2-catalyzed allylation of aldehydes with allylboronates in aqueous media exclusively afford the α-addition products. This reaction was also applied to alkylallylation, chloroallylation, and alkoxyallylation reactions. The role of water is discussed. Copyright

Mechanistic dichotomy in the asymmetric allylation of aldehydes with allyltrichlorosilanes catalyzed by chiral pyridine N-oxides

Detailed kinetic and computational investigation of the enantio- and diastereoselective allylation of aldehydes 1 with allyltrichlorosilanes 5, employing the pyridine N-oxides METHOX (9) and QUINOX (10) as chiral organocatalysts, indicate that the reaction can proceed through a dissociative (cationic) or associative (neutral) mechanism: METHOX apparently favors a pentacoordinate cationic transition state, while the less sterically demanding QUINOX is likely to operate via a hexacoordinate neutral complex. In both pathways, only one molecule of the catalyst is involved in the rate- and selectivity-determining step, which is supported by both experimental and computational data. Copyright

Conformationally rigid chiral pyridine N-oxides as organocatalyst: Asymmetric allylation of aldehydes

A pyridine unit with a conformationally rigid chiral backbone has been designed and synthesized in an enantiomerically pure form to utilize in the Lewis base-catalyzed Sakurai-Hosomi-Denmark-type allylation reaction. The chiral pyridine N-oxide in 1:1 mix

On the mechanism of asymmetric allylation of aldehydes with allyltrichlorosilanes catalyzed by QUINOX, a chiral isoquinoline N-oxide

Allylation of aromatic aldehydes 1a-m with allyl- and crotyl- trichlorosilanes 2-4, catalyzed by the chiral N-oxide QUINOX (9), has been found to exhibit a significant dependence on the electronics of the aldehyde, with p-(trifluoromethyl)benzaldehyde 1g

Chiral phosphoramide-catalyzed enantioselective addition of allylic trichlorosilanes to aldehydes. Preparative studies with bidentate phosphorus-based amides

On the basis of the mechanistic insight that more than one Lewis basic moiety (phosphoramide) is involved in the rate- and stereochemistry-determining step of enantioselective allylation, bidentate chiral phosphoramides were developed. Different chiral phosphoramide moieties were connected by tethers of methylene chains of varying length. The rate and enantioselectivity of allylation with allyltrichlorosilane promoted by the bidentate phosphoramides was found to be highly dependent on the tether length. A new phosphoramide based on a 2,2′-bispyrrolidine skeleton has been designed and afforded good yield, efficient turnover, and high enantioselectivity in allylation reactions. The synthesis of enantiopure 2,2′-bispyrrolidine was easily accomplished on large scale by photodimerization of pyrrolidine followed by resolution with L(or D)-tartaric acid. The scope of the allylation reaction was examined with variously substituted allylic trichlorosilanes and unsaturated aldehydes. This method has been applied to the construction of stereogenic, quaternary centers by the addition of unsymmetrically γ-disubstituted allylic trichlorosilanes.

A concise synthesis of (-)-cytoxazone and (-)-4-epi-cytoxazone using chlorosulfonyl isocyanate

A concise synthesis of (-)-cytoxazone and its stereoisomer (-)-4-epi-cytoxazone, novel cytokine modulators, has been accomplished each in six steps from readily available p-anisaldehyde with good diastereoselectivity. Key steps in the synthesis include th

Enantioselective catalytic addition of allyl organometallic reagents to aldehydes promoted by [Cr(Salen)]: The hidden role played by weak Lewis acids in metallo-Salen promoted reactions

In this paper, we present the data obtained from kinetic analysis and from NLE study in the [Cr(Salen)] catalysed addition of allyl halides to aldehydes. The results show the key role played by weak Lewis acids in the catalytic system. Weak Lewis acids such as manganese salts and the [Cr(Salen)X] complex drive the stereochemistry of the reaction toward a high level of diastero- and enantioselectivity. Therefore, the Lewis acids and their properties must be taken into account in the rational design of metallo-Salen mediated processes.