Total synthesis and absolute stereochemical assignment of (-)-communesin F.
A concise asymmetric total synthesis of (-)-communesin F (∼6% overall yield in the longest linear sequence of 19 steps) is described. It features an unprecedented intramolecular oxidative coupling strategy for the elaboration of the requisite spiro-fused indoline moiety. Other notable elements are the use of TBS-protected (S)-phenylglycinol as a chiral auxiliary to induce the asymmetric formation of the spiro-fused indoline part, the mesylate-mediated formation of its G ring, and the introduction of the A ring at the final stage via intramolecular Staudinger reaction. This intramolecular Staudinger reaction proceeded smoothly at 80 °C, providing an additional example illustrating that twisted amides are more reactive than simple amides. Along with the total synthesis, we were able to assign the absolute configuration of natural communesin F as 6R,7R,8R,9S,11R.
Zuo
Zhiwei
Z
State Key Laboratory of Bioorganic and Natural Products Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 354 Fenglin Lu, Shanghai 200032, China.
Xie
Weiqing
W
Ma
Dawei
D
D006576:Heterocyclic Compounds, 4 or More Rings / Q000138:chemical synthesis / Q000737:chemistry*; D015394:Molecular Structure; D013237:Stereoisomerism
D006576:Heterocyclic Compounds, 4 or More Rings; C522025:communesin F