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DOI: 10.1055/s-0033-1340438
Pd-Catalyzed Asymmetric Ring Opening of Azabenzonorbornadienes
Enantioselective Palladium-Catalyzed Ring-Opening Reaction of Azabenzonorbornadienes with Methyl 2-Iodobenzoate: An Efficient Access to cis-Dihydrobenzo[c]phenanthridinones.
Adv. Synth. Catal. 2013;
355: 2833-2838
Publication History
Publication Date:
13 December 2013 (online)
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Significance
In the presence of electron-rich chiral spirophosphine ligands, I2 as key additive, and zinc powder as reducing agent, Pd(MeCN)2Cl2 efficiently catalyzes the ring opening of azabenzonorbornadiene with various 2-iodobenzoates. The resulting enantioenriched cis-dihydrobenzo[c]phenanthridinones serve as core structure of numerous optically active natural products.
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Comment
The use of easily available organic halides instead of organometallic reagents and the construction of fused ring systems with multiple stereocenters via the tandem asymmetric ring-opening–cyclization process make the strategy remarkably efficient. A direct application of the present methodology was demonstrated via the concise total synthesis of (+)-chelidonine.
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