Synthesis of (+)-sch 642305 by a biomimetic transannular Michael reaction.
[reaction: see text] The synthesis of (+)-Sch 642305 (1) has been completed in 17 steps in 1.6% overall yield. Transannular Michael reaction of 2b with NaH in THF provided cyclohexenone 23 stereospecifically. Heating 23 in TFA/CDCl(3) provided a 3:1 equilibrium mixture of 23 and 25, which was hydrolyzed to give (+)-6-epi-Sch 642305 (24) and (+)-Sch 642305 (1), respectively.
Snider
Barry B
BB
Department of Chemistry, MS 015, Brandeis University, Waltham, Massachusetts 02454-9110, USA.
Zhou
Jingye
J
D018942:Macrolides / Q000138:chemical synthesis* / Q000737:chemistry; D018716:Molecular Mimicry; D015394:Molecular Structure; D010407:Penicillium / Q000737:chemistry; D013237:Stereoisomerism
D018942:Macrolides; C482741:Sch 642305