175356-64-6Relevant academic research and scientific papers
Novel approach to the ansamycin antibiotics macbecin I and herbimycin A. A formal total synthesis of (+)-macbecin I
Martin, Stephen F.,Dodge, Jeffrey A.,Burgess, Laurence E.,Limberakis, Chris,Hartmann, Michael
, p. 3229 - 3246 (2007/10/03)
The asymmetric syntheses of 25 and 29, which constitutes the C(3)-C(15) segment of the stereochemically complex ansa chain of (+)-macbecin I (1) and herbimycin A (2), respectively, have been achieved. The approach features the furan-hydropyranone transfor
Total Synthesis of (+)-Macbecin I
Baker, Raymond,Castro, Jose L.
, p. 47 - 65 (2007/10/02)
The first total enantiospecific synthesis of (+)-macbecin I has been performed in a convergent manner by coupling the epoxide (3) with a higher order cyanocuprate derived from the vinyl iodide (46).The required absolute stereochemistries at C(20)-C(21) and C(12)-C(13) were accessible by enantioselective aldol condensations while that at C(16)-C(17) was achieved by Sharpless epoxidation of a secondary (E)-allylic alcohol (39), efficiently prepared by reaction of the aldehyde (37) with CrCl2-CH3CHI2.The remaining stereocentre at C-18 was introduced by an asymmetric hydroxylation of an enolate.Macrocyclization of the amino acid (59) to give the lactam (60) was successfully achieved by its reaction with either 2-mesitylenesulphonyl chloride or bis(2-oxo-3-oxazolidinyl)phosphinic chloride.Incorporation of the carbamate functionality was achieved by reaction of the parent hydroxy derivative with sodium cyanate and trifluoroacetic acid.The final oxidation to the quinone was accomplished with cerium(IV) ammonium nitrate.
