240118-48-3

Upstream product

• 6628-79-1 3-methyllevulinic acid 
• 151-50-8 potassium cyanide 
• 49620-10-2 (+)-trans-β-methyl-γ-carboxy-γ-valerolactone 
• 60375-12-4 (2R-trans)-tetrahydro-2,3-dimethyl-5-oxo-2-furancarboxylic acid methyl ester 
• 863423-70-5 (3R)-2,3-dimethylpentanedioic acid 1-methyl ester 
• 863423-69-2 (3R)-4-diethylcarbamoyl-2,3-dimethylbutyric acid methyl ester 
• 863423-72-7 (4R,5R)-5-(2-methoxy-[1,3]dithian-2-yl)-4,5-dimethyldihydrofuran-2-one 
• 863423-71-6 (4R)-4-[1,3]dithian-2-ylidene-3-methylpentanoic acid diethylamide 
• 60375-12-4 methyl trans-β-methyl-γ-carboxy-γ-valerolactone 
• 74-90-8 hydrogen cyanide 
• 1465764-36-6 C₁₄H₁₂ClNO₄ 
• 1465764-29-7 methyl (2R,3S)-2,3-dimethyl-5-oxotetrahydrofuran-2-carboxylate 
• 1465764-27-5 methyl (R)-2,5-dihydro-2,3-dimethyl-5-oxofuran-2-carboxylate 
• 1465764-07-1 phenyl 3-[(R)-5H-2-(2-chlorophenyl)-5-methyl-4-oxooxazol-5-yl]-3-butenoate 

Downstream Products

• 60660-35-7 (2R-trans)-tetrahydro-2,3-dimethyl-5-oxo-2-furancarboxylic acid 

Relevant academic research and scientific papers

1,4-addition reaction of 5H-oxazol-4-ones to allenic esters and ketones catalyzed by chiral guanidines

In this paper, a chiral guanidine-catalyzed 1,4-addition reaction of 5H-oxazol-4-ones to allenic esters and ketones is described. 5H-Oxazol-4-ones substituted with a 2-chlorophenyl group were suitable pronucleophiles that gave high enantioselectivities. Subsequent hydrolysis of the obtained adduct gave the corresponding γ-butenolide ester without loss of enantiopurity and was transformed into (+)-crobarbatic acid in a few steps.

Oxidative rearrangement of 2-alkoxy-3,4-dihydro-2H-pyrans: stereocontrolled synthesis of 4,5-cis-disubstituted tetrahydrofuranones including whisky and cognac lactones and crobarbatic acid

Oxidation of 2-alkoxy-3,4-dihydro-2H-pyrans 3 with dimethyldioxirane or MTO/urea-H2O2 followed by Jones oxidation leads to rearrangement and stereocontrolled formation of 4,5-cis-disubstituted tetrahydrofuranones. The method is applied to the synthesis of the whisky lactone 9, cognac lactone 10 and crobarbatic acid 17.

Anodic cyclization reactions and the synthesis of (-)-crobarbatic acid

A synthesis of (-)-crobarbatic acid is reported along with the first use of a vinyl-substituted ketene dithioacetal as a coupling partner for an anodic cyclization reaction. The use of the vinyl-substituted ketene dithioacetal enables the construction of a cyclic product having a tetrasubstituted carbon with a relative stereochemistry opposite to that originally obtained from the cyclization.

Oxidative cyclizations and the synthesis of lactones: A streamlined synthesis of epi-crobarbatic acid

While anodic cyclizations have been shown to be compatible with the synthesis of lactones, the previous synthetic route to the starting materials was cumbersome and limited the overall utility of the approach. In this manuscript, a new strategy is reported that allows for very rapid synthesis of the electrolysis substrates. In addition, an efficient conversion of the ortho ester product obtained from the oxidative cyclization to a lactone acid is reported. The result is a dramatically improved synthetic strategy for the synthesis of functionalized tetrahydrofuranones.

Highly diastereoselective Michael addition of α-hydroxy acid derivatives and enantioselective synthesis of (+)-crobarbatic acid

(matrix presented) Michael addition of enolates of 2a and 2b to α,β-unsaturated esters took place selectively on different faces (Si and Re, respectively) of the double bond to give the corresponding products 4 and 5, respectively, with >98% de. Subsequen

The synthesis of (-)-cis- and (-)-trans-crobarbatic acid

The synthesis of both cis- and trans-crobarbatic acid is reported. The five-step sequence proceeds in high yield and with control of both relative and absolute stereochemistry. The key step in the synthesis is the Birch reductive alkylation of a chiral furoic acid which sets the absolute stereochemistry of the products. The stereochemistry of the compounds described was proven unambiguously by X-ray crystallography on one synthetic intermediate and on trans-crobarbatic acid.

Chiral synthesis of the necic acid components, crobarbatic acid and integerrinecic acid lactone

Samarium(II) diiodide-promoted regioselective fragmentation of the γ-halogeno esters 12 and 13 afforded the olefins 14 and 20, respectively, which were converted into the necic acid components, crobarbatic acid and a known advanced intermediate of integer

Diastereodivergent Control in the Reactions of Allylic and Allenic Organometallic Reagents with Pyruvates

The reaction of crotyl-9-BBN (4a) with pyruvates (3) produced the threo (anti) isomer 5 either predominantly or exclusively.On the other hand, the reaction of allenic organometallic reagents 18 (M = B or Ti) gave the erythro (syn) isomer 20 preferentially

Diastereoselective Reactions of Pyruvates with But-2-enyl Organometallic Compounds. Stereocontrol at the Tertiary Carbon Centre

The reaction of pyruvates (3) with but-2-enyl-9-borabicyclononane (2a) or its α-silyl and α-stannyl substituted derivatives (10) produced the threo-isomer stereoselectively; the latter reaction was applied to the synthes