title: Total synthesis and correct absolute configuration of malyngamide U.
abstract: The enantioselective synthesis of the previously proposed structure of malyngamide U (1) was accomplished in 18 steps from (S)-(+)-carvone. The key steps involved a hydroxymethylation of (S)-(+)-carvone and an asymmetric Henry reaction of aldehyde (+)-5, as well as condensation with the acid 3. The 1H and 13C NMR data of the synthetic compound 1 were not consistent with the data of the reported malyngamide U. The C-2' epimer of compound 1 was therefore synthesized by a similar reaction sequence. While the NMR data of C-2' epimer 23 were in full agreement with those of the reported product, the discrepancy in the specific rotation data suggested the correct structure of malyngamide U should be structure 2, in which the absolute configuration of the amine part was enantiomeric with that in compound 23. Then the correct absolute configuration of revised malyngamide U (2) was confirmed by the similar synthesis from (R)-(-)-carvone.
authors.affiliation: State Key Laboratory of Applied Organic Chemistry and College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou, 730000, People's Republic of China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Li
authors.forename: Jian-Peng
authors.initials: JP
authors.lastname: Feng
authors.forename: Wen-Hua
authors.initials: WH
authors.lastname: Wang
authors.forename: Jie
authors.initials: J
authors.lastname: Chen
authors.forename: Xiao-Ping
authors.initials: XP
authors.lastname: Cao
mesh_terms: D000438:Alcohols / Q000737:chemistry; D000447:Aldehydes / Q000737:chemistry; D003512:Cyclohexanones / Q000138:chemical synthesis* / Q000737:chemistry; D005229:Fatty Acids, Monounsaturated / Q000138:chemical synthesis* / Q000737:chemistry; D015394:Molecular Structure
chemical_list: D000438:Alcohols; D000447:Aldehydes; D003512:Cyclohexanones; D005229:Fatty Acids, Monounsaturated; C474704:malyngamide U