title: Total syntheses of cis-cyclopropane fatty acids: dihydromalvalic acid, dihydrosterculic acid, lactobacillic acid, and 9,10-methylenehexadecanoic acid.
abstract: cis-Cyclopropane fatty acids (cis-CFAs) are widespread constituents of the seed oils of subtropical plants, membrane components of bacteria and protozoa, and the fats and phospholipids of animals. We describe a systematic approach to the synthesis of enantiomeric pairs of four cis-CFAs: cis-9,10-methylenehexadecanoic acid, lactobacillic acid, dihydromalvalic acid, and dihydrosterculic acid. The approach commences with Rh2(OAc)4-catalyzed cyclopropenation of 1-octyne and 1-decyne, and hinges on the preparative scale chromatographic resolution of racemic 2-alkylcycloprop-2-ene-1-carboxylic acids using a homochiral Evan's auxiliary. Saturation of the individual diastereomeric N-cycloprop-2-ene-1-carbonylacyloxazolidines, followed by elaboration to alkylcyclopropylmethylsulfones, allowed Julia-Kocienski olefination with various ω-aldehyde-esters. Finally, saponification and diimide reduction afforded the individual cis-CFA enantiomers.
authors.affiliation: School of Chemistry and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria 3010, Australia. sjwill@unimelb.edu.au.
authors.forename: Sayali
authors.initials: S
authors.lastname: Shah
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: White
authors.forename: Spencer J
authors.initials: SJ
authors.lastname: Williams
mesh_terms: D000480:Alkynes / Q000737:chemistry; D002264:Carboxylic Acids / Q000737:chemistry; D002384:Catalysis; D005227:Fatty Acids / Q000138:chemical synthesis*; D010080:Oxazoles / Q000737:chemistry; D010169:Palmitic Acids / Q000138:chemical synthesis*; D012238:Rhodium / Q000737:chemistry; D013237:Stereoisomerism
chemical_list: D000480:Alkynes; D002264:Carboxylic Acids; D005227:Fatty Acids; D010080:Oxazoles; D010169:Palmitic Acids; C070383:9,10-methylenehexadecanoic acid; C029355:dihydrosterculic acid; C042001:1-octyne; D012238:Rhodium; C028716:phytomonic acid