Total Synthesis of (±)-Decytospolides A and B

Abstract

Total synthesis of (±)-decytospolides A and B have been accomplished by an efficient and stereoselective construction of 2,6-cistetrahydropyrans by an intramolecular oxa-conjugate addition reaction.

α‐Aminoxy Oligopeptides: Synthesis, Secondary Structure, and Cytotoxicity of a New Class of Anticancer Foldamers

“…The A alerts in the checkcif procedure are solely caused by the low resolution of the experiment at the synchrotron. Crystallographic data:s pace group P2 1 2 1 2 1 , a = 5.1627(1) , b = 23.5630 (5) , c = 41.5043(10) ,2 4874 measured reflections, synchrotron radiation (l = 0.9677 ), 3489 unique reflections used for the refinement, wR 2 (all) = 0.0836, R 1 (all) = 0.0359, CCDC 1420774 contains the supplementary crystallographic data for this paper.T hese data are provided free of charge by The Cambridge Crystallographic Data Centre.…”

“…[4] The aminoxy amide bond is resistantt oe nzymatic degradation, and peptide analogs constructed from a-aminoxy acids show remarkable conformational stability,w hich hasb een demonstrated by Yang andc oworkers through quantum chemical calculations,N MR, FT-IR, and CD spectroscopy. [4,5] The preferred secondary structure of homochiral a-aminoxy peptides is stabilized by strongi ntramolecular hydrogen bonds betweent he C=O i oxygen and the NÀH i + 2 protonl eadingt os o-called a NÀOt urns. [4] It has been hypothesized that oligomers can adopt ac onformation consistingo fc onsecutive a NÀOt urns resultingi na1 .8 8 -helix.…”

“…To the best of our knowledgeo nly one solid-phase-supported protocol for the synthesis of a-aminoxy oligopeptides has been published thus far. [5] The methodr eported by Shin and coworkers allowed the preparation of as eries of pentamers. [5] In the initial phase of this project, we attemptedt op repare the hexamer 1a (Phth-NO Ile-NO Ile-NO Ile-NO Ile-NO Leu-NO Leu-NH 2 ) utilizing this published protocol.…”

“…[5] The methodr eported by Shin and coworkers allowed the preparation of as eries of pentamers. [5] In the initial phase of this project, we attemptedt op repare the hexamer 1a (Phth-NO Ile-NO Ile-NO Ile-NO Ile-NO Leu-NO Leu-NH 2 ) utilizing this published protocol. However,t he desired product was only obtainedi nl ow crude yield (20 %) and purity (33 %), which is in line with previous reports about difficulties in the synthesis of peptides equences containing repetitive aliphatic side chains, such as sec-butyl.…”

“K‐synthesis”: Recent advancements in natural product synthesis enabled by unique methods and strategies development in Korea

“…The resulting alcohol 167 was then brominated and further derivatized to produce the synthetic sample of (−)‐bisezakyne A ( 169 ), in which the spectroscopic data completely matched those of the natural sample. The collaborative researches by the Kim and the Lee groups have been further exemplified by total synthesis of natural products such as macakurzin C ( 170 ), 55 (±)‐decytospolides A ( 171 ) and B ( 172 ), 56 and (+)‐srilankenyne ( 173 , Scheme 11c). 57 …”