Tetrahedron letters

Directed ortho metalation-cross coupling links. Carbamoyl rendition of the baker-venkataraman rearrangement. Regiospecific route to substituted 4-hydroxycoumarins

…, AJM da Silva, CC Lopes, RSC Lopes, V Snieckus

Index: Kalinin, Alexey V.; Da Silva, Alcides J. M.; Lopes, Claudio C.; Lopes, Rosangela S. C.; Snieckus, Victor Tetrahedron Letters, 1998 , vol. 39, # 28 p. 4995 - 4998

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Citation Number: 61

Abstract

Abstract: A new carbamoyl Baker-Venkataraman rearrangement (4) which allows a general. synthesis of substituted 4-hydroxycoumarins 8 in 43X?% overall yields is described; the intermediate arylketones 6 are efficiently prepared (59-91% yields) via a Directed ortho Metalation-Negishi cross coupling protocol from arylcarbamates 5 and the overall sequence provides a regiospecific anionic Friedel-Crafts complement for the construction of orrho- ...