- Three-Step Catalytic Asymmetric Total Syntheses of 13-Methyltetrahydroprotoberberine Alkaloids
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(S,R)-N-PINAP was identified to be the chiral ligand for highly enantioselective CuI-catalyzed reaction of tetrahydroisoquinolines (THIQs), alkynes, and 2-bromobenzaldehyde derivatives. This enables us to accomplish the first asymmetric total synthesis of 12 natural 13-methyltetrahydroprotoberberine (13-MeTHPB) alkaloids in only three catalytic steps with 47-64% overall yields. In addition, the Pd-catalyzed reductive Heck cyclization was successfully extended to three Pd-catalyzed domino reactions (Heck/Suzuki, Heck/Sonogashira, and Heck/Heck), which greatly expands the synthetic utility of this catalytic strategy and allows expeditious access to 13-substituted tetrahydroprotoberberines for further bioactivity evaluation.
- Zhou, Shiqiang,Tong, Rongbiao
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p. 1594 - 1597
(2017/04/13)
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- A General, Concise Strategy that Enables Collective Total Syntheses of over 50 Protoberberine and Five Aporhoeadane Alkaloids within Four to Eight Steps
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A concise, catalytic, and general strategy that allowed efficient total syntheses of 22 natural 13-methylprotoberberines within four steps for each molecule is reported. This synthesis represents the most efficient and shortest route to date, featuring three catalytic processes: CuI-catalyzed redox-A3 reaction, Pd-catalyzed reductive carbocyclization, and PtO2-catalyzed hydrogenation. Importantly, this new strategy to the tetracyclic framework has also been applied to the collective concise syntheses of >30 natural protoberberines (without 13-methyl group) and five aporhoeadane alkaloids.
- Zhou, Shiqiang,Tong, Rongbiao
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supporting information
p. 7084 - 7089
(2016/05/19)
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