Total synthesis of indolizidine alkaloid (-)-209D: overriding substrate bias in the asymmetric rhodium-catalyzed [2+2+2] cycloaddition.
CO! You had me at hello: The use of chiral biphenyl-based phosphoramidite ligands on rhodium provides an efficient [2+2+2] cycloaddition between terminal alkyl alkynes and alkenyl isocyanates (see scheme). The cycloaddition proceeds through a CO migration pathway, and facilitates a rapid four-step asymmetric synthesis of indolizidine (-)-209D.
Yu
Robert T
RT
Department of Chemistry, Colorado State University, Fort Collins, CO 80523, USA.
Lee
Ernest E
EE
Malik
Guillaume
G
Rovis
Tomislav
T
D000470:Alkaloids / Q000138:chemical synthesis* / Q000737:chemistry; D002384:Catalysis; D003500:Cyclization; D026121:Indole Alkaloids / Q000138:chemical synthesis* / Q000737:chemistry; D054836:Indolizidines / Q000138:chemical synthesis* / Q000737:chemistry; D012238:Rhodium / Q000737:chemistry*; D013237:Stereoisomerism
C540151:209D compound; D000470:Alkaloids; D026121:Indole Alkaloids; D054836:Indolizidines; D012238:Rhodium