Synthetic studies toward pseurotin a

Asymmetric Total Synthesis of Pseurotin A

“…by Kakeya and Osada et al and found to inhibit the endothelial migration induced by vascular endothelial growth factor . Because of the unprecedented, densely functionalized core structure of the pseurotins and azaspirene, their total synthesis poses a significant challenge, and several synthetic endeavors aimed at the total synthesis of pseurotin A have been reported . We have completed the first total synthesis of a member of this class of compounds, that of azaspirene, in which a Sharpless asymmetric dihydroxylation, a MgBr 2 -mediated, highly diastereoselective Mukaiyama aldol reaction, and a NaH-mediated, intramolecular addition of an amide to an alkyne are employed as key steps .…”

“…The lithium enolate of 14 7 reacted with side-chain aldehyde 3 ( E : Z = 4:1) prepared by the literature procedure,6a affording the aldol product 15 in 54% yield (diastereomeric ratio = 2:1) with recovery of ketone 14 in 45% yield (Scheme ). Oxidation of aldols 15 with the Dess−Martin periodinane 15 (DMP) in CH 2 Cl 2 proceeded smoothly, providing 1,3-diketone 16 .…”