Comparative study of the Kumada, Negishi, Stille, and Suzuki-Miyaura reactions in the synthesis of the indole alkaloids hippadine and pratosine.
The total synthesis of hippadine by a tandem metalation/cross-coupling/lactamization strategy was investigated starting from either 7-bromoindole or a 6-halogenated methyl piperonate. The Kumada and Negishi cross-coupling reactions failed to provide any of the desired product. However, the Stille and Suzuki reactions furnished hippadine in low yields starting from the electron-deficient methyl 6-iodo- and 6-bromopiperonate, respectively. Starting from the metalated indole, only the Suzuki reaction occurred, affording hippadine in 67-74% and pratosine in 62% isolated yield.
Mentzel
Uffe V
UV
Department of Chemistry, Technical University of Denmark, Building 201, Kemitorvet, DK-2800 Kgs. Lyngby, Denmark.
Tanner
David
D
Tønder
Janne E
JE
D000470:Alkaloids / Q000138:chemical synthesis* / Q000737:chemistry; D047151:Amaryllidaceae Alkaloids / Q000138:chemical synthesis* / Q000737:chemistry; D002384:Catalysis; D015394:Molecular Structure; D010084:Oxidation-Reduction
D000470:Alkaloids; D047151:Amaryllidaceae Alkaloids; C102970:pratosine; C039688:hippadine