Preparation of Tri- and Tetrasubstituted Allenes viaRegioselective Lateral Metalation of Benzylic (Trimethylsilyl)alkynesUsing TMPZnCl·LiCl.
- Resource Type
- Article
- Authors
- Quinio, Pauline; Francois, Cyril; Escribano Cuesta, Ana; Steib, Andreas K.; Achrainer, Florian; Zipse, Hendrik; Karaghiosoff, Konstantin; Knochel, Paul
- Source
- Organic Letters. Feb2015, Vol. 17 Issue 4, p1010-1013. 4p.
- Subject
- *PALLADIUM catalysts
*SUBSTITUTION reactions
*REGIOSELECTIVITY (Chemistry)
*METALATION
*ALKYNES
*CHEMICAL sample preparation
- Language
- ISSN
- 1523-7060
The zincation of various 1-(trimethylsilyl)-3-aryl-1-propyneswithTMPZnCl·LiCl followed by a Pd-catalyzed coupling with aryl halidesprovides arylated allenes in 52–92% yield. Subsequent metalationwith TMPZnCl·LiCl and cross-coupling with a second differentaryl halide provides regioselectively tetrasubstituted allenes in42–70% yield. This sequence can be performed in a one-pot procedure.DFT calculations and NMR studies support the formation of allenylzincand propargyllithium intermediates starting from 1-(trimethylsilyl)-3-phenyl-1-propyne. [ABSTRACT FROM AUTHOR]