Biomimetic total syntheses of cassiarins A and B.
Total syntheses of cassiarins A and B have been efficiently accomplished using a common strategy with biomimetic considerations. Key reactions involved in this synthesis include a Negishi-type coupling, a Ag(I)-promoted formation of the tricyclic 8H-pyrano[2,3,4-de]chromen-8-one core, and a sequential amine-condensation and cyclization. Three new analogues of cassiarin A bearing different substituents at the C-11 position were synthesized in parallel from the same intermediate. In addition, two other transformations to the key tricyclic cores and cassiarins A and B were achieved from corresponding chemically equivalent precursors.
State Key Laboratory of Bioorganic and Natural Products Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 354 Fenglin Road, Shanghai 200032, China.
Yuan-Shan
YS
Yao
Zhu-Jun
ZJ
Yao
D000114:Acetylene / Q000737:chemistry; D040761:Biomimetic Materials / Q000138:chemical synthesis* / Q000737:chemistry; D006575:Heterocyclic Compounds, 3-Ring / Q000138:chemical synthesis* / Q000737:chemistry; D007659:Ketones / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure
D006575:Heterocyclic Compounds, 3-Ring; D007659:Ketones; C524027:cassiarin A; C524026:cassiarin B; D000114:Acetylene