252558-59-1Relevant academic research and scientific papers
Enantioselective Total Synthesis of Fluvirucinin B1
Guignard, Guillaume,Llor, Núria,Molins, Elies,Bosch, Joan,Amat, Mercedes
, p. 1788 - 1791 (2016/05/19)
A convergent synthesis of fluvirucinin B1 from acid ent-6a and nitrile ent-9, involving an organocopper coupling, a stereoselective allylation, a ring-closing metathesis reaction, and a stereoselective hydrogenation as the key steps, is reported. The starting building blocks have been prepared in a straightforward manner from a common phenylglycinol-derived lactam 1. An unprecedented regioselective oxidation of phenylglycinol-derived secondary amines 5 to carboxylic acids 6 has been developed.
Total synthesis of rutamycin B and oligomycin C
Panek,Jain
, p. 2747 - 2756 (2007/10/03)
The asymmetric synthesis of the macrolide antibiotics (+)-rutamycin B (1) and (+)-oligomycin C (2) is described. The approach relied on the synthesis and coupling of the individual spiroketal fragments 3a and 3b with the C1-C17 polyproprionate fragment 4. The preparation of the spiroketal fragments was achieved using chiral (E)-crotylsilane bond construction methodology, which allowed the introduction of the stereogenic centers prior to spiroketalization. The present work details the synthesis of the C19-C28 and C29-C34 subunits as well as their convergent assembly through an alkylation reaction of the lithiated N,N-dimethylhydrazones 6 and 8 to afford the individual linear spiroketal intermediates 5a and 5b, respectively. After functional group adjustment, these advanced intermediates were cyclized to their respective spiroketal-coupling partners 40 and 41. The requisite polypropionate fragment was assembled in a convergent manner using asymmetric crotylation methodology for the introduction of six of the nine-stereogenic centers. The use of three consecutive crotylation reactions was used for the construction of the C3-C12 subunit 32. A Mukaiyama-type aldol reaction of 35 with the chiral α-methyl aldehyde 39 was used for the introduction of the C12-C13 stereocenters. This anti aldol finished the construction of the C3-C17 advanced intermediate 36. A two-carbon homologation completed the construction of the polypropionate fragment 38. The completion of the synthesis of the two macrolide antibiotics was accomplished by the union of two principal fragments that was achieved with an intermolecular palladium-(0) catalyzed cross-coupling reaction between the terminal vinylstannanes of the individual spiroketals 3a and 3b and the polypropionate fragment 4. The individual carboxylic acids 46 and 47 were cyclized to their respective macrocyclic lactones 48 and 49 under Yamaguchi reaction conditions. Deprotection of these macrolides completed the synthesis of the rutamycin B and oligomycin C.
High-yielding enantioselective synthesis of the macrolactam aglycon of Sch 38516 from two units of (2R)-2-ethyl-4-penten-1-ol
Martin, Manuel,Mas, Gemma,Urpi, Felix,Vilarrasa, Jaume
, p. 3086 - 3089 (2007/10/03)
The same precursor - namely, (2R)-2-ethyl-4-penten-1-ol - was used to obtain fragments C9-C13 and C1-C8 of 1, the aglycon of Sch 38516 (which is active against Candida sp.) and fluvirucin B1 (which is active against influenza A virus). The key
