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.
Yao
Yuan-Shan
YS
State Key Laboratory of Bioorganic and Natural Products Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 354 Fenglin Road, Shanghai 200032, China.
Yao
Zhu-Jun
ZJ
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