75658-88-7

Upstream product

• 4295-92-5 (3R,5S)-3,5-dimethyldihydro-2H-pyran-2,6(3H)-dione 
• 2121-69-9 (2R,4S)-2,4-dimethylpentane-1,5-diol 
• 130288-43-6 (2S,4R)-5-(tert-Butyl-dimethyl-silanyloxy)-2,4-dimethyl-pentanoic acid (1-phenyl-ethyl)-amide 
• 82917-27-9 [2S,4R]-2,4-dimethyl-pentanedioic acid monomethyl ester 
• 96612-17-8 [2R,4S]-2,4-dimethyl-pentanedioic acid monomethyl ester 
• 82898-94-0 (l,u)-und (u,u)-3,5-Dimethyltetrahydropyran-2-ol 
• 108913-57-1 (2R,4S)-2,4-Dimethyl-pentanedioic acid mono-((1R,7S,7aR)-7-methyl-hexahydro-pyrrolizin-1-yl) ester 
• 194933-34-1 (R)-3,5-Dimethyl-5,6-dihydro-pyran-2-one 
• 454482-19-0 (2S,4R)-5-hydroxy-2,4-dimethyl-N-[(S)-1-phenylethyl]pentanamide 
• 480441-20-1 (4R,2''S)-4-benzyl-3[2,4-dimethylpent-4-enoyl]oxazolidin-2-one 
• 4098-66-2 2,4-dimethyl-pentanedioic acid dimethyl ester 
• 100-53-8 phenylmethanethiol 
• 2121-67-7 2,4-dimethylglutaric acid 
• 32475-72-2 3,5-dimethyl-tetrahydropyran-2-one 

Downstream Products

• 130288-45-8 Benzoic acid (E)-(2R,4S)-6-methoxy-2,4-dimethyl-hex-5-enyl ester 
• 130288-46-9 Benzoic acid (2R,4S)-2,4-dimethyl-6-oxo-hexyl ester 
• 130304-59-5 Benzoic acid (6E,8E)-(2R,4R,10R)-2,4,8,10-tetramethyl-dodeca-6,8-dienyl ester 

Relevant academic research and scientific papers

Synthetic routes to the stereoisomers of 2,4-dimethylpentane-1,5-diol derivatives

Five different routes to every stereoisomer of non-symmetric derivatives of 2,4-dimethylpentanedioic acid and/or of O-monoprotected 2,4-dimethylpentane- 1,5-diols, which are common building blocks for the total synthesis of many polypropionates, have been investigated. Alkylation of the lithium enolate of N-propanoylpseudoephedrine turned out to be the most appropriate method, in connection with the synthesis of fragment C1-C5 of amphidinolide K.

Desymmetrization of acid anhydride with asymmetric esterification catalyzed by chiral phosphoric acid

Asymmetric desymmetrization of σ-symmetric acid anhydrides was achieved with chiral phosphoric acid as a Br?nsted acid catalyst. The key of success was finding of benzhydrol and 2,2-diphenylethanol as the nucleophiles of choice. The corresponding half esters were obtained in good yields with high selectivity.

Intramolecular stereoselective protonation of aldehyde-derived enolates

Picking sides: Asymmetric protonation of the titled compounds poses a most significant challenge and has been addressed by taking advantage of internal protonation and subsequent hemiacetal formation to avoid epimerization (see scheme). The substrates employed in these transformations can be easily accessed through a sequence of vinylogous aldol reactions with subsequent conjugate reductions.

Asymmetric hydrogenation routes to deoxypolyketide chirons

Asymmetric hydrogenations of monoenes and dienes were performed to obtain terminal deoxypolyketide fragments A and the corresponding internal Chirons B and C. The chiral N-heterocyclic carbene catalyst 1 was used throughout. Modest selectivities for hydrogenations of simple monoenes relayed into high selectivities for preparations of the terminal deoxypolyketide fragments in which either two hydrogenations or one and an optically pure starting material were used. Curiously, the face selectivities for hydrogenation of α,β-unsaturated esters were consistently opposite to those that had been observed for styrene and stilbene derivatives in previous work, and to closely related allylic alcohol and ether derivatives in this work. Plausible mechanisms for this differing behavior were deduced by using DFT calculations. It appears that the origin of the unusual stereoselectivity for the ester derivatives is transient metal-coordination of the ester carbonyl whereas there is no evidence that the allylic alcohol or ethers coordinate. The routes developed to α,ω-functionalized internal deoxypolyketide fragments are extremely practical. These begin with the Roche ester being converted into alkene and, in one case, diene derivatives. Catalyst control prevails in the hydrogenations of these substrates, but there is a significant "substrate vector" (a term we used to describe the influence of the substrate on a catalyst-controlled reaction). This is determined by minimization of 1,3-allylic strain and, in some cases, syn pentane interactions. This substrate vector can be constructively paired with the (dominant) catalyst vector by use of the appropriate enantiomer of 1. In the hydrogenation of a diene derivative, two chiral centers could be formed simultaneously with overall 11:1.0 selectivity; this is the first time this has been achieved in any asymmetric synthesis of a deoxypolyketide fragment. Throughout, diastereo-selectivities of the crude material in the syntheses of α,ω-functionalized internal deoxypolyketide fragments were in excess of 11:1.0 and chromatographically purified samples could be isolated in high yields with dr (dr = diastereomeric ratio) values consistently in excess of 40:1.0.

A Diels-Alder macrocyclization enables an efficient asymmetric synthesis of the antibacterial natural product abyssomicin C

An efficient and highly diastereoselective intramolecular Diels-Alder reaction is the basis of a concise asymmetric synthesis of the potent antibacterial natural product abyssomicin C (see formula). The complexity of the target structure was reduced to three fragments and required two carbonyl addition reactions to achieve key bond formations. (Figure Presented).

All-catalytic, efficient, and asymmetric synthesis of α,ω- diheterofunctional reduced polypropionates via "one-pot" Zr-catalyzed asymmetric carboalumination - Pd-catalyzed cross-coupling tandem process

A highly efficient method for the synthesis of stereochemically pure (≥99% ee and >50/1 dr) α,ω-diheterofunctional reduced polypropionates has been developed. The essential features of the method are represented by the conversion of inexpensive styrene in

Highly enantioselective catalytic thiolysis of prochiral cyclic dicarboxylic anhydrides utilizing a bifunctional chiral sulfonamide

(Chemical Equation Presented) A catalytic desymmetrization is achieved for various prochiral dicarboxylic anhydrides with yields of 87-100% and ee values of 83-98% through the title reaction (see scheme; Bn = benzyl). The bifunctional effect of the chiral sulfonamide catalyst was clarified on the basis of unsuccessful asymmetric induction by using the related chiral sulfonamides.

Toward a total synthesis of okilactomycin. 1. A direct, enantiocontrolled route to the western sector

A synthesis of the western half of the macrocyclic ring framework of the antitumor antibiotic okilactomycin is described. The strategy employed rests on an efficient synthesis of meso-2,4-dimethylglutaric anhydride and ensuing resolution via reaction with (S)-(-)-α-methylbenzylamine, diborane reduction, and selective crystallization. Following acid-catalyzed cyclization to (2S,4R)-2,4-dimethyl-δ-valerolactone, an acyclic stereocontrol strategy was adopted to achieve chain lengthening with appropriate incorporation of functionality. The sensitive aldehyde 2 was further homologated to β-keto ester 17 in a model reaction sequence performed to simulate its ultimate projected coupling to 3.

Synthesis of Microcolin B, a Potent New Immunosuppressant Using an Efficient Mixed Imide Formation Reaction

Microcolin B, a potent new immunosuppressant isolated from blue-green alga Lyngbya majuscula off the Venezuelan coast, has been made using a methyl-directed asymmetric hydrogenation reaction with rhodium on alumina catalyst on lactone 4 for the synthesis of the key (R,R)-2,4-dimethyl-octanoic acid fragment 1. A new, direct mixed imide formation reaction was also developed for the production of the unusual prolylpyrrolen-2-one 2 portion of microcolin. The pentafluorophenyl ester of CBZ-proline 5 was reacted with the lithium imidate of lactam 6, providing the mixed imide in 80% yield. Coupling of acid 1 with the N-terminus of the tripeptide, followed by coupling with pyrrolylproline 2, gave microcolin B. The new mixed-imide forming reaction was also applied to a formal total synthesis of microcolin A. The pentafluorophenyl ester of TBS-protected cis-hydroxyproline was coupled with lactam 6, and the resultant imide was converted to the key pyrrolylproline made previously for microcolin A.

Synthesis of 2,4-Dimethylglutaric Acid Monoesters via Enzyme-catalyzed Asymmetric Alcoholysis of meso-2,4-Dimethylglutaric Anhydride

1-(2-Methylpropyl) 5-hydrogen (2R,4S)-2,4-dimethylpentanedioate with an enantiomeric excess of 90percent was obtained in a yield of 72percent from meso-2,4-dimethylpentanedioic anhydride and 2-methylpropanol by an asymmetric alcoholysis catalyzed by the l