Yusuke Yasui

Polymeric Ethyl Glyoxylate in an Asymmetric Aldol Reaction Catalyzed by Diarylprolinol

Diarylprolinol was found to be an effective organocatalyst of the direct, enantioselective aldol reaction of commercially available polymeric ethyl glyoxylate, affording gamma-ethoxycarbonyl-beta-hydroxy aldehydes, versatile synthetic intermediates, in good yield with excellent enantioselectivity.

Diarylprolinol in an Asymmetric, Direct Cross-Aldol Reaction with Alkynyl Aldehydes

The direct cross‐aldol reaction of alkynyl aldehydes catalyzed by a trifluoromethylated diarylprolinol provides a practical route for the highly enantioselective synthesis of chiral β‐alkynyl‐β‐hydroxy aldehydes. Good anti selectivity and excellent enantioselectivity were obtained in the reactions of silylpropynals, which afford synthetically useful chiral building blocks.

Total Synthesis of the 7,10‐Epimer of the Proposed Structure of Amphidinolide N, Part I: Synthesis of the C1–C13 Subunit

Amphidinolide N, the structure of which has been recently revised, is a 26-membered macrolide featuring allyl epoxide and tetrahydropyran moieties with 13 chiral centers. Due to its challenging structure and extraordinary potent cytotoxicity, amphidinolide N is a highly attractive target of total synthesis. During our total synthesis studies of the 7,10-epimer of the proposed structure of amphidinolide N, we have synthesized the C1-C13 subunit enantio- and diastereoselectively. Key reactions include an l-proline catalyzed enantioselective intramolecular aldol reaction, Evans aldol reaction, Sharpless asymmetric epoxidation and Tamao-Fleming oxidation. To aid late-stage manipulations, we also developed the 4-(N-benzyloxycarbonyl-N-methylamino)butyryl group as a novel ester protective group for the C9 alcohol.