Palladium catalyzed indolization

Details Palladium catalyzed indolization Palladium catalyzed indolization

1997-08-07

1998-09-15

McKane, Joseph K.

Organic compounds -- part of the class 532-570 series

Organic compounds

Four or more ring nitrogens in the bicyclo ring system

544364, 5443666, 544369, 546187, 546201, 5462724, 548229, 5482664, 5483121, 548465, 548466, 548467, 548405, C07D41312, C07D20904

Patent

active

058080643

ABSTRACT:
We have found that 2-unsubstituted indoles of structural formula (IV) can be cost-effectively synthesized in high yield by the palladium-catalyzed coupling/ring closure of a 2-halo or 2-trifluoromethylsulfonyloxy aniline (I) and an acyl silane derivative (II), followed by deprotection of the silyl protecting groups. ##STR1## The process of the present invention is particularly useful to form indoles containing acid-labile substituents such as triazole, acetyl, ketal, cyano, and carbamate, or indoles having a good leaving group in the benzyl position. The advantages of the present process are that it does not require the use of triphenyl phosphine or tetrabutyl ammonium chloride or lithium chloride. When applied to 5-triazolyl substituted indoles, the present process also eliminates the tendency of triazolyl polymerization in the Fischer indole synthesis.

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