215173-33-4

Upstream product

• 557-93-7 2-bromoprop-1-ene 
• 5445-77-2 (2R)-2-methyl-3-phenylpropanal 
• 77943-96-5 (2R)-2-methyl-3-phenyl-1-propanol 
• 13291-18-4 isopropenylmagnesium bromide 

Downstream Products

• 195257-52-4 (2R,3E)-5-bromo-2,4-dimethyl-3-pentenylbenzene 
• 440641-45-2 (1S,3S,4S,5R)-1-((R,E)-3,5-dimethyl-6-phenylhex-3-en-1-yl)-4-hydroxy-4,5-bis(methoxycarbonyl)-2,8-dioxabicyclo[3.2.1]octane-3-carboxylic acid 
• 215173-36-7 (1S,3R,4S,5R)-1-[(3E,5R)-3,5-dimethyl-6-phenyl-3-hexenyl]-4-hydroxy-3-hydroxymethyl-4,5-bis(methoxycarbonyl)-2,8-dioxabicyclo[3.2.1]octane 
• 215173-34-5 (2R,3E)-2,4-dimethyl-6-phenylsulfonyl-3-hexenylbenzene 

Relevant academic research and scientific papers

Synthesis of Alkyl Citrates (-)-CJ-13,981, (-)-CJ-13,982, and (-)-L-731,120 via a Cyclobutene Diester

An efficient and step-economic new approach to alkyl citrate natural products from a cyclobutene diester is presented. The key sequence involves a formal [2 + 2]-cycloaddition of a silylketene acetal with dimethylacetylene dicarboxylate to provide the cyclobutene diester 14 with 4.5:1 stereoselectivity. Exposure of diester 14 in acidic methanol effected a hydrolysis, intramolecular oxy-Michael reaction, and cyclobutanone methanolysis cascade to give the triester 15. Iodination and elimination then afforded a key alkyl citrate alkene intermediate, which was converted into the natural products (-)-CJ-13,982 (1), (-)-CJ-13,981 (2), and (-)-L-731,120 (3) via a cross-metathesis and subsequent reduction.

Novel approach to the Zaragozic acids. Enantioselective total synthesis of 6,7-dideoxysqualestatin H5

The total synthesis of 6,7-dideoxysqualestatin H5 (3) has been completed by a concise approach that features the stereoselective intramolecular vinylogous aldol reaction of the furoic ester 25a to give 30 or its trimethylsilyl ether derivative 34, which possess the requisite absolute stereochemistry at C(3)-C(5) of 3. Compound 34 was reduced to the saturated bislactone 39, and the C(1) side chain subunit 47 was introduced leading to a mixture of the hemiacetals 48 and the corresponding ketone 49. When this mixture was stirred with methanolic acid, transketalization occurred to give a mixture of 50 and the spirocyclic methyl acetals 51a,b. Oxidation of the primary alcohol group in 50 followed by saponification of the two remaining ester groups gave 3. The longest linear sequence in the synthesis commences with commercially available erythronolactone (26) and requires 17 chemical steps with only 10 isolated intermediates.