Institut für Organische Chemie und Biochemie, Albert-Ludwigs-Universität Freiburg, Freiburg im Breisgau, Germany.
Org Lett. 2011 May 20;13(10):2730-3. doi: 10.1021/ol2008318. Epub 2011 Apr 28.
A (DHQN)(2)AQN-promoted asymmetric dihydroxylation (92% ee) of the allyl chloride derived from enynol (E)-13 and an 8-step sequence provided access to the hydroxyethylated furanone (R)-21. Oxidation with MnO(2) furnished 50% furanone (+)-(R)-2a and 2.7% isomeric furanone (+)-(R)-3a. (R)-2a possesses the accepted constitution of (+)-gregatin B but its spectra are different. Surprisingly, (+)-(R)-3a equals the natural product. Analogous structure reassignments are due for the gregatins A and C-E, the aspertetronins A-B, graminin A, and the penicilliols A and B.
(A)DHQN)(2)AQN 促进的烯炔醇 (E)-13 衍生的烯丙基氯的不对称双羟化反应（92%ee），以及 8 步序列提供了羟基化呋喃酮 (R)-21。用 MnO(2)氧化得到 50%的呋喃酮 (+)-(R)-2a 和 2.7%的非对映异构体呋喃酮 (+)-(R)-3a。(R)-2a 具有（+）-gregatin B 的公认结构，但它们的光谱不同。令人惊讶的是，(+)-(R)-3a 等于天然产物。gregatins A 和 C-E、aspertetronins A-B、graminin A 以及 penicilliols A 和 B 的类似结构重新分配也是如此。
