Combined Directed Ortho Metalation/Cross-Coupling Strategies:  Synthesis of the Tetracyclic A/B/C/D Ring Core of the Antitumor Agent Camptothecin

2004 ◽  
Vol 69 (23) ◽  
pp. 7816-7821 ◽  
Author(s):  
Tam Nguyen ◽  
Markus A. Wicki ◽  
Victor Snieckus
Keyword(s):  
Cross Coupling ◽  
Antitumor Agent ◽  
Ortho Metalation ◽  
Ring Core ◽  
Coupling Strategies

Combined directed ortho-metalation, remote metalation, and Stille cross-coupling strategies. Concise stereoselective synthesis of polysubstituted 9H-fluoren-9-ones

Tetrahedron ◽  
2008 ◽  
Vol 64 (15) ◽  
pp. 3331-3336 ◽  
Author(s):  
Anne-Sophie Castanet ◽  
David Tilly ◽  
Jean-Baptiste Véron ◽  
Subhendu S. Samanta ◽  
Asish De ◽  
...  
Keyword(s):  
Stereoselective Synthesis ◽  
Cross Coupling ◽  
Ortho Metalation ◽  
Coupling Strategies

ortho and remote metalation – cross coupling strategies. Total synthesis of the naturally occurring fluorenone dengibsinin and the azafluoranthene alkaloid imeluteine

1994 ◽  
Vol 72 (1) ◽  
pp. 227-236 ◽  
Author(s):  
J. -m. Fu ◽  
B. -p. Zhao ◽  
M. J. Sharp ◽  
V. Snieckus
Keyword(s):  
Natural Products ◽  
Total Synthesis ◽  
Dimethyl Ether ◽  
Cross Coupling ◽  
Naturally Occurring ◽  
Ortho Metalation ◽  
Coupling Approach ◽  
Successful Approach ◽  
Coupling Strategies

The total synthesis of the naturally occurring fluorenone, dengibsinin (7a), and the azafluoranthene alkaloid, imeluteine (30e), is described. Using combined ortho metalation – cross coupling sequences that terminate in Friedel–Crafts (18b → 6d) and remote metalation (21a,b → 6c,d) reactions, the synthesis of fluorenone dimethyl ethers 6c and 6d is reported. 6c and 6d were shown not to be identical to dengibsinin dimethyl ether and dengibsin dimethyl ether, respectively, derived from the natural products. This work, together with synthetic and structural evidence from Sargent and Talapatra, led to the reassignment of structures for dengibsinin (7a) and dengibsin (7b). Using the metalation – cross coupling approach, the synthesis of the reassigned dengibsinin (7a) is presented. Two alternate unsuccessful approaches to imeluteine are briefly described (31 + 32 and 33 + 34). The successful approach incorporates the remote metalation – double cyclization, 43 → 44, as the key step.

scholarly journals Directed ortho-Metalation—Cross Coupling Strategies. N-Cumyl Arylsulfonamides. Facile Deprotection and Expedient Route to 7- and 4,7-Substituted Saccharins.

ChemInform ◽  
2007 ◽  
Vol 38 (36) ◽  
Author(s):  
Jerome Blanchet ◽  
Todd Macklin ◽  
Patrick Ang ◽  
Costa Metallinos ◽  
Victor Snieckus
Keyword(s):  
Cross Coupling ◽  
Ortho Metalation ◽  
Coupling Strategies
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