Concise Syntheses of bis-Strychnos Alkaloids (-)-Sungucine, (-)-Isosungucine, and (-)-Strychnogucine B from (-)-Strychnine.
The first chemical syntheses of complex, bis-Strychnos alkaloids (-)-sungucine (1), (-)-isosungucine (2), and (-)-strychnogucine B (3) from (-)-strychnine (4) is reported. Key steps included (1) the Polonovski-Potier activation of strychnine N-oxide; (2) a biomimetic Mannich coupling to forge the signature C23-C5' bond that joins two monoterpene indole monomers; and (3) a sequential HBr/NaBH3 CN-mediated reduction to fashion the ethylidene moieties in 1-3. DFT calculations were employed to rationalize the regiochemical course of reactions involving strychnine congeners.
Department of Chemistry, Temple University, 1901 N. 13th, St. Philadelphia, Pa, 19122, USA.
Senzhi
S
Zhao
Department of Chemistry, Temple University, 1901 N. 13th, St. Philadelphia, Pa, 19122, USA.
Christiana N
CN
Teijaro
Department of Chemistry, Temple University, 1901 N. 13th, St. Philadelphia, Pa, 19122, USA.
Heng
H
Chen
Department of Chemistry, Temple University, 1901 N. 13th, St. Philadelphia, Pa, 19122, USA.
Gopal
G
Sirasani
Department of Chemistry, Temple University, 1901 N. 13th, St. Philadelphia, Pa, 19122, USA.
Shivaiah
S
Vaddypally
Department of Chemistry, Temple University, 1901 N. 13th, St. Philadelphia, Pa, 19122, USA.
Michael J
MJ
Zdilla
Department of Chemistry, Temple University, 1901 N. 13th, St. Philadelphia, Pa, 19122, USA.
Graham E
GE
Dobereiner
Department of Chemistry, Temple University, 1901 N. 13th, St. Philadelphia, Pa, 19122, USA. randrade@temple.edu.
Rodrigo B
RB
Andrade
D000470:Alkaloids / Q000138:chemical synthesis* / Q000737:chemistry; D003497:Cyclic N-Oxides / Q000737:chemistry*; D026121:Indole Alkaloids / Q000138:chemical synthesis* / Q000737:chemistry; D007211:Indoles / Q000737:chemistry*; D013237:Stereoisomerism; D013331:Strychnine / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry* / Q000302:isolation & purification; D031451:Strychnos / Q000737:chemistry*
D000470:Alkaloids; D003497:Cyclic N-Oxides; D026121:Indole Alkaloids; D007211:Indoles; C464957:isosungucine; C428164:strychnogucine B; C083068:strychnine N-oxide; C030374:indole; D013331:Strychnine
alkaloids; biomimetic synthesis; natural products; strychnine; sungucine