Multi-component coupling synthesis of polycyclic pyrrole derivatives via Ir- and Rh-catalyzed cycloisomerizations with microwave heating
作者:Yoshihiko Yamamoto、Hiroki Hayashi
DOI:10.1016/j.tet.2007.07.105
日期:2007.10
which were further transformed into polycyclic pyrrole-2-carboxylates via iridium-catalyzed cycloisomerization/Diels–Alder cycloaddition/dehydrogenation sequence under conventional and microwave heating conditions. The corresponding β-amino acid analogues were obtained from the Ir-catalyzed reaction of enynes prepared from lithium amides of allylamines with methyl non-2-en-4-ynoate. The Cu-catalyzed
CuBr2-catalyzed three-component coupling of N-benzylallylamine, ethyl glyoxalate, and terminal alkynes afforded glycine-tethered 1,6-enynes, which were further transformed into polycyclic pyrrole-2-carboxylates via novel cycloisomerization/Diels-Alder cycloaddition/dehydrogenation sequence under iridium-catalyzed conditions.
Synthesis of α,α-Disubstituted α-Amino Esters: Nucleophilic Addition to Iminium Salts Generated from Amino Ketene Silyl Acetals
作者:Shingo Hata、Hiroshi Koyama、Makoto Shimizu
DOI:10.1021/jo201692x
日期:2011.12.2
Alkoxycarbonyl iminium species are prepared easily by the oxidation of tetrasubstituted amino ketene silyl acetals, and subsequent nucleophilic addition of Grignard reagents to the iminium salts gives α,α-disubstituted α-amino ester derivatives in moderate to good yields, in which aryl and ethynyl substituents are readily introduced.