Synthesis of α-Keto-Imides via Oxidation of Ynamides
摘要:
A de novo preparation of alpha-keto-imides via ynamide oxidation is described. With a number of alkyne oxidation conditions screened, a highly efficient RuO2-NaIO4 mediated oxidation and a DMDO oxidation have been identified to tolerate a wide range of ynamide types. In addition to accessing a wide variety of a-keto-imides, the RuO2-NaIO4 protocol provides a novel entry to the vicinal tricarboryl motif via oxidation of push-pull ynamides, and imido acylsilanes from silyl-substituted ynamides. Chemoselective oxidation of ynamides containing olefins can be achieved by using DMDO, while the RuO2-NaIO4 protocol is not effective. These studies provide further support for the synthetic utility of ynamides.
Rhodium(I)-Catalyzed [2 + 2 + 2] Cycloadditions of Ynamides in the Synthesis of Amide-Substituted Chiral Biaryls
作者:Michael R. Tracey、Jossian Oppenheimer、Richard P. Hsung
DOI:10.1021/jo061683p
日期:2006.10.1
Rhodium(I)-catalyzed [2 + 2 + 2] cycloadditions of sterically encumbered aryl-substituted ynamides with various diynes are described here. These cycloadditions provide the synthesis of an array of new chiral amide-substituted biaryls that can be useful in future chiral ligand designs.
A Rhodium(I)-Catalyzed Demethylation−Cyclization of <i>o-</i>Anisole-Substituted Ynamides in the Synthesis of Chiral 2-Amido Benzofurans
作者:Jossian Oppenheimer、Whitney L. Johnson、Michael R. Tracey、Richard P. Hsung、Pei-Yuan Yao、Renhe Liu、Kang Zhao
DOI:10.1021/ol0707362
日期:2007.6.1
A Rh(I)-catalyzed demethylation-cyclization sequence for a direct transformation of o-anisole-substituted ynamides to benzofurans is described here. The Ag salt functions synergistically with Rh(I) for the key demethylation step.