Castro-Stephens indole synthesis

Applications of the original Castro-Stephens indole synthesis were described by Yamamoto (A-benzyhndole,... 

Scheme 1 The Castro-Stephens Indole Synthesis [Cu(phen)(PPh3)2]N03...

Recentiy, glyoxylyl chlorides 3, formed in situ by direct glyoxylation of electron-rich heterocycles such as indoles and pyrroles with oxalyl chloride, have been coupled in the Cu-catalyzed Stephen-Castro reaction to terminal arylacetylenes [11]. The resulting heterocycHc ynediones 4 are valuable electrophihc building blocks for the synthesis of various pharmaceutically relevant compounds (Scheme 9.3). 

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