Title of article :
Nodulisporic acid side-Chain modifications: access to the 2″, 3″, 4″, and 6″ registers
Author/Authors :
Prasun K. Chakravarty، نويسنده , , Thomas L. Shih، نويسنده , , Steven L. Colletti، نويسنده , , Michelle B. Ayer، نويسنده , , Christine Snedden، نويسنده , , Howard Kuo، نويسنده , , Sriram Tyagarajan، نويسنده , , Lynn Gregory، نويسنده , , Michelle Zakson-Aiken، نويسنده , , Wesley L. Shoop، نويسنده , , Dennis M. Schmatz، نويسنده , , MatthewJ. Wyvratt، نويسنده , , Michael H. Fisher، نويسنده , , Peter T. Meinke، نويسنده ,
Abstract :
Efficient routes to access the 2″, 3″, 4″, and 6″ registers of the nodulisporic acid (NsA) side chain are disclosed. A mild one-carbon, Ph2C=NCH2C N mediated homologation of NsAʹs 3″-aldehyde permitted access to the 4″-register. Curtius reaction of NsAʹs 3″-acid yielded the corresponding 2″-aldehyde 4 from which the unnatural Δ2″,3″-olefin isomer 2b was obtained. In addition, Arndt–Eistert reactions of the parent NsA permitted a one-carbon homologation to the 6″ register. These efforts identified new analogues with significant flea activity and illustrated the biological significance of unsaturation at the 1″,2″ register.
