75553-24-1

Upstream product

• 36219-40-6 1-bromo-2-hydroxy-2-methyl-3-butene 
• 766-04-1 benzyllithium 
• 1838-94-4 isoprene epoxide 
• 19319-26-7 (Z)-2-methyl-2-buten-1-ol 
• 768-56-9 4-Phenylbut-1-ene 
• 116760-89-5 (Z)-methyl 2-methyl-5-phenylpent-2-enoate 
• 114377-78-5 ethyl (Z)-2-methyl-5-phenyl-pent-2-enoate 

Downstream Products

• 25634-93-9 2-methyl-5-phenyl pentanol 
• 36613-11-3 rac-2-Methyl-5-phenylpentanal 
• 4215-86-5 isohexylbenzene 
• 213456-58-7 1-bromo-2-methyl-5-phenyl-2Z-pentene 

Relevant academic research and scientific papers

Photoredox/Nickel-Catalyzed Single-Electron Tsuji–Trost Reaction: Development and Mechanistic Insights

A regioselective, nickel-catalyzed photoredox allylation of secondary, benzyl, and α-alkoxy radical precursors is disclosed. Through this manifold, a variety of linear allylic alcohols and allylated monosaccharides are accessible in high yields under mild reaction conditions. Quantum mechanical calculations [DFT and DLPNO-CCSD(T)] support the mechanistic hypothesis of a Ni0 to NiII oxidative addition pathway followed by radical addition and inner-sphere allylation.

Synthesis of Z- or E-Trisubstituted Allylic Alcohols and Ethers by Kinetically Controlled Cross-Metathesis with a Ru Catechothiolate Complex

The first examples of kinetically controlled cross-metathesis reactions that generate Z- or E-trisubstituted alkenes are disclosed. Transformations are catalyzed by ≤6.0 mol % of a Ru catechothiolate complex and afford trisubstituted allylic alcohols and

Synthesis of Chiral Tertiary Boronic Esters by Oxime-Directed Catalytic Asymmetric Hydroboration

Chiral boronic esters are useful intermediates in asymmetric synthesis. We have previously shown that carbonyl-directed catalytic asymmetric hydroboration (CAHB) is an efficient approach to the synthesis of functionalized primary and secondary chiral boronic esters. We now report that the oxime-directed CAHB of alkyl-substituted methylidene and trisubstituted alkene substrates by pinacolborane (pinBH) affords oxime-containing chiral tertiary boronic esters with yields up to 87 % and enantiomeric ratios up to 96:4 e.r. The utility of the method is demonstrated by the formation of chiral diols and O-substituted hydroxylamines, the generation of quaternary carbon stereocenters through carbon-carbon coupling reactions, and the preparation of chiral 3,4,4-trisubstituted isoxazolines.

The cinchona primary amine-catalyzed asymmetric epoxidation and hydroperoxidation of α,β-unsaturated carbonyl compounds with hydrogen peroxide

Using cinchona alkaloid-derived primary amines as catalysts and aqueous hydrogen peroxide as the oxidant, we have developed highly enantioselective Weitz-Scheffer-type epoxidation and hydroperoxidation reactions of α,β-unsaturated carbonyl compounds (up to 99.5:0.5 er). In this article, we present our full studies on this family of reactions, employing acyclic enones, 5-15-membered cyclic enones, and α-branched enals as substrates. In addition to an expanded scope, synthetic applications of the products are presented. We also report detailed mechanistic investigations of the catalytic intermediates, structure-activity relationships of the cinchona amine catalyst, and rationalization of the absolute stereoselectivity by NMR spectroscopic studies and DFT calculations.

Catalytic asymmetric epoxidation of α-branched enals

An asymmetric catalytic epoxidation of α-branched, α,β-unsaturated aldehydes is presented. A highly synergistic combination of a primary cinchona-based amine and a chiral phosphoric acid was found to promote the reaction with excellent enantiocontrol for α-monosubstituted and α,β-disubstituted enals.

Mn(III)-based oxidative free-radical 6-endo cyclizations of Z- trisubstituted alkenes

Oxidative free-radical cyclization of Z-trisubstituted alkene 6a gave the expected octahydrophenanthrenes 9 (11%) and 10 (24%), lactone 17 (10%), and octahydrophenanthrene 4 (25%), which was obtained from E-trisubstituted alkene 1a. Cyclization of 6b provided the expected hydrindane 11 (25%), cyclopentane 18b (10%) formed by 5-exo cyclization, and hydrindane 5 (13%), which was obtained from E-trisubstituted alkene 1b. These results provide valuable information on the mechanism of Mn(III)-based oxidative radical cyclizations and indicate the profound effect of alkene geometry on the stereochemistry of radical cyclizations.

Acyclic Stereoselection in the Ortho Ester Claisen Rearrangement

The ortho ester Claisen rearrangement of trisubstituted allylic alcohols exhibits significant levels of diastereoselection. In E allylic alcohols, a 1,3-diaxial interaction develops in the chairlike transition state leading to the anti isomer, rendering the reaction syn selective by a factor of 3-5 to 1. In Z allylic alcohols, the 1,3-diaxial interaction develops in the transition state leading to the syn isomer, generating an anti:syn selectivity of 6-15 to 1. The relative stereochemistry of the syn isomer was confirmed independently by the synthesis of the mycotoxin botryodiplodin.

Cob(I)alamin als Katalysator. 6. Mitteilung . Bildung und Fragmentierung von Alkylcobalaminen, ein Gleichgewichtsprozess zwischen nukleophiler Addition und reduktiver Fragmentierung

Isolated olefines can be saturated using catalytic amounts of cob(I)alamin in aqueous acetic acid; as electron source an excess of zinc dust is added to the solution containing the homogeneous catalyst.During this overall hydrogenation of isolated double bonds intermediate alkylcobalamins are formed (compare e.g.Schemes 2, 4, 5, 7 and 12).Clear evidence is presented that the nucleophilic attack on the isolated double bond is carried out by cob(I)alamin and not by cob(II)alamin also present in the system (see Scheme 3b and 3c).As this catalytic saturation of olefins depends on the pH of the solution, characterized by a slow reaction at pH=7.0 compared to the same reduction in aqueous acetic acid (see Scheme 2, 2 -> 4, and Scheme 3a), it is reasonable to accept the participation of an electrophilic attack by a proton during the generation of alkylcobalamins. - We use the term nucleophilic addition to describe the formation of alkylcobalamins from a proton, an olefin and cob(I)alamin (compare Schemes 4-7 and 12).A special sequence of experiments showed the nucleophilic addition to beregioselective.Preferentially the higher substituted alkylcobalamin revealed to be produced.Therefore, the nucleophilic addition of cob(I)alamin follows the Markownikoff rule (compare chap. 4: formation and fragmentation of β-hydroxyalkylcobalamins).Under the reaction conditions applied the intermediate alkylcobalamins can be present in base-on and base-off forms.They are known to exist as octahedral complexes and might also be stable to some extent as tetragonal-pyramidal species.In addition the base-off forms can partially be protonated at the dimethylbenzimidazole moiety in aqueous acetic acid (compare Scheme 12).From this equilibrium of intermediate alkylcobalamins three modes of decay disclosed to be possible: (i) The reductive fragmentation leading to an olefin, a proton, and cob(I)alamin is the formal retro-reaction of the nucleophilic addition (see Schemes 2, 4 and 6-12).This equilibrium of an associated alkylcobalamin and the corresponding dissociation products revealed to be a fast process compared to the reductive cleavage of the Co, C-bond cited below (s. (iii)). (ii) As the second reaction pattern an oxidative fragmentation producing an olefin, a hydroxy anion (or water, respectively) and cob(III)alamin has been observed (see Schemes 7, 8, 10 and 12). (iii) The slow reductive cleavage of the Co, C-bond, initiated by addition of electrons (see ), was the third reaction path observed (see Schemes 2, 4-8 and 10-12. - The stereochemistry of the three transformations originating from the intermediate alkylcobalamins is unknown up to now.The antiperiplanar pattern of the fragmentation reactions presented in the Schemes has been chosen arbitrarily (see e.g.Scheme 12).

COPPER(I)-CATALYZED REACTION OF ISOPRENE BROMOHYDRIN WITH ORGANOLITHIUM REAGENT

The reaction of isoprene bromohydrin (1-bromo-2-methyl-3-buten-2-ol) (1) with ethyl-, propyl- and butyllithium in the presence of copper(I) iodide leads to the exclusive formation of the vinyl group migrated 2-alkyl-4-penten-2-ols (3d-3f), in contrast to