γ-Allenic α-amino acids can be obtained by a three-step sequence from the phosphates of α-allenic alcohols: i) palladium-catalyzed alkylation of a Schiff base derived from glycine ester by these phosphates, ii) acidic hydrolysis of the imine functionality, and iii) saponification of the resulting amino esters.
We developed a novel synthetic method of the corestructure of dragmacidin E bearing a 7-membered ring-fused bis(indolyl)pyrazinone skeleton. Formation of the 7-membered ring-fused tricyclic indole skeleton was accomplished using a palladium-catalyzed Heck insertion–allylic amination cascade. Vicinal difunctionalization of the 7-membered ring was realized via a rhodium-catalyzed aminoacetoxylation
Selective Azetidine and Tetrahydropyridine Formation via Pd-Catalyzed Cyclizations of Allene-Substituted Amines and Amino Acids
作者:Floris P. J. T. Rutjes、Kim C. M. F. Tjen、Larissa B. Wolf、Willem F. J. Karstens、Hans E. Schoemaker、Henk Hiemstra
DOI:10.1021/ol990700c
日期:1999.9.1
[GRAPHICS]By choosing the right substituents either highly functionalized unusual four-membered ring amino acids or the isomeric pipecolic acid derivatives are obtained in enantiomerically pure form. Starting material is a linear allene containing amino acid that has been resolved via biocatalysis.
Pd-Catalyzed Cascade Cyclization by Intramolecular Heck Insertion of an Allene–Allylic Amination Sequence: Application to the Synthesis of 3,4-Fused Tricyclic Indoles
A novel Pd-catalyzed cascade cyclization by intramolecular Heck insertion of an alleneallylic amination sequence was developed. Allenes tethered to ortho-iodoaniline derivatives at the meta-position were reacted with 5-10 mol % of Pd catalyst and 4 equiv of K2CO3 in DMSO at 90 degrees C, producing 3,4-fused tricyclic 3-alkylidene indoline derivatives in moderate to excellent yield. The reaction products were divergently transformed into three types of 3,4-fused tricyclic indole derivatives, successfully demonstrating the versatile properties of the reaction products.