Palladium catalyzed indolization
US5808064A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 7, 1997 |
| Grant date | Sep 15, 1998 |
| Priority date | — |
| Expiry date | Aug 7, 2017 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02P20/55
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.