Total synthesis of mycalamide A and 7-epi-mycalamide A.
[formula: see text] The final stages of a total synthesis of mycalamide A are described. A key step is the aldol reaction (mismatched) of imide 4 and aldehyde 5 which provided a ca. 5:4 mixture of aldols 10a and 10b, with incorrect C(7) stereochemistry. Elaboration of the 10a-10b mixture to mycalamide A required epimerization of C(7) at the stage of beta-keto imide 11. Alternatively, Swern oxidation of the 10a-10b mixture under conditions that minimize C(7) epimerization led to 7-epi-mycalamide A selectively.
Roush
W R
WR
Department of Chemistry, University of Michigan, Ann Arbor 48109, USA. roush@umich.edu
Pfeifer
L A
LA
D000970:Antineoplastic Agents / Q000138:chemical synthesis / Q000737:chemistry; D007202:Indicators and Reagents; D008387:Marine Toxins / Q000138:chemical synthesis / Q000737:chemistry; D008958:Models, Molecular; D008968:Molecular Conformation; D011714:Pyrans / Q000138:chemical synthesis* / Q000737:chemistry
D000970:Antineoplastic Agents; D007202:Indicators and Reagents; D008387:Marine Toxins; D011714:Pyrans; C059646:mycalamide A