197777-48-3Relevant academic research and scientific papers
Total synthesis of rhizoxin D, a potent antimitotic agent from the fungus Rhizopus chinensis
White, James D.,Blakemore, Paul R.,Green, Neal J.,Hauser, E. Bryan,Holoboski, Mark A.,Keown, Linda E.,Nylund Kolz, Christine S.,Phillips, Barton W.
, p. 7750 - 7760 (2007/10/03)
Rhizoxin D (2) was synthesized from four subunits, A, B, C, and D representing C3-C9, C10-C13, C14-C19, and C20-C27, respectively. Subunit A was prepared by cyclization of iodo acetal 21, which set the configuration at C5 of 2 through a stereoselective addition of the radical derived from dehalogenation of 21 at the β carbon of the (Z)-α,β-unsaturated ester. Aldehyde 29 was obtained from phenylthioacetal 24 and condensed with phosphorane 30, representing subunit B, in a Wittig reaction that gave the (E,E)-dienoate 31. This ester was converted to aldehyde 33 in preparation for coupling with subunit C. The latter in the form of methyl ketone 55 was obtained in six steps from propargyl alcohol. An aldol reaction of 33 with the enolate of 55 prepared with (+)-DIPCl gave the desired β-hydroxy ketone 56 bearing a (13S)-configuration in a 17-20:1 ratio with its (13R)-diastereomer. After reduction to anti diol 57 and selective protection as TIPS ether 58, the C15 hydroxyl was esterified to give phosphonate 59. An intramolecular Wadsworth-Emmons reaction of aldehyde 62, derived from δ-lactone 60, furnished macrolactone 63, which was coupled in a Stille reaction with stannane 68 to give 2 after cleavage of the TIPS ether.
Studies on the total synthesis of the macrolide antitumor agent rhizoxin. 2. Synthesis of the C14-C26 segment
White, James D.,Holoboski, Mark A.,Green, Neal J.
, p. 7333 - 7336 (2007/10/03)
An asymmetric synthesis of the C14-C26 segment of rhizoxin is described in which the three stereogenic centers are derived from a γ-lactone; stannylcupration-methylation of a terminal alkyne is used to generate an (E)-iodoalkene for Stille coupling with a dienylstannane that produces the conjugated (E,E,E)-triene unit of rhizoxin.
