highly stereoselective asymmetric 6π-azaelectrocyclization utilizing the novel 7-alkyl substituted...

2002 indole derivatives, isoindole derivatives

indole derivatives, isoindole derivativesR 0140

50 - 088Highly Stereoselective Asymmetric 6π-Azaelectrocyclization Utilizingthe Novel 7-Alkyl Substituted cis-1-Amino-2-indanols: Formal Syn-thesis of 20-Epiuleine. — A novel asymmetric 6π-azaelectrocyclizationis developed based on the reaction of (E)-3-carbonyl-2,4,6-trienal compoundswith chiral cis-1-amino-2-indanol derivatives under mild conditions. (III) isobtained as a single isomer, while using more general aldehydes containinglinear alkyl or phenyl substituents afford mixtures of diastereoisomers. Removalof the chiral indanol moiety is achieved by treatment with LiAlH4 and MnO2

to give the corresponding amino alcohols. The present method can be appliedto the synthesis of ketone (X) which is the key intermediate of the strychnosindole alkaloid. — (TANAKA, KATSUNORI; KATSUMURA, SHIGEO; J.Am. Chem. Soc. 124 (2002) 33, 9660-9661; Sch. Sci. Technol., Kwansei GakuinUniv., Sanda, Hyogo 669, Japan; EN)

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