Enantioselective organocatalytic construction of pyrroloindolines by a cascade addition-cyclization strategy: synthesis of (-)-flustramine B.
Pyrroloindoline and bispyrroloindoline are a subclass of alkaloid structural motifs that commonly exhibit biological activity. An enantioselective organocatalytic approach to the synthesis of pyrroloindoline architecture is described. The addition-cyclization of tryptamines with alpha,beta-unsaturated aldehydes in the presence of imidazolidinone catalysts 1 and 8 provides pyrroloindoline adducts in high yield and excellent enantioselectivities. This transformation is successful for a wide range of tryptamine and alpha,beta-unsaturated aldehyde substrates. This amine-catalyzed sequence has been extended to the enantioselective construction of furanoindoline frameworks. Application of this pyrroloindoline-forming reaction to natural product synthesis has been accomplished in the context of the enantioselective synthesis of (-)-flustramine B.
Austin
Joel F
JF
Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA.
Kim
Sung-Gon
SG
Sinz
Christopher J
CJ
Xiao
Wen-Jing
WJ
MacMillan
David W C
DW
D000447:Aldehydes / Q000737:chemistry; D000470:Alkaloids / Q000138:chemical synthesis* / Q000737:chemistry; D002384:Catalysis; D003500:Cyclization; D007093:Imidazoles / Q000737:chemistry; D026121:Indole Alkaloids; D007211:Indoles / Q000138:chemical synthesis / Q000737:chemistry*; D011758:Pyrroles / Q000138:chemical synthesis / Q000737:chemistry*; D013237:Stereoisomerism; D014363:Tryptamines / Q000737:chemistry
D000447:Aldehydes; D000470:Alkaloids; D007093:Imidazoles; D026121:Indole Alkaloids; D007211:Indoles; D011758:Pyrroles; D014363:Tryptamines; C041254:flustramine B