A simple and highly efficient P,O-type ligand for Suzuki-Miyaura cross-coupling of aryl halides.
ABSTRACT A simple and efficient hemilabile-type phosphine ligand, found to be highly effective in Suzuki-Miyaura cross-coupling of aryl chlorides with generally low Pd-catalyst loading (0.05%), was prepared in one step based on an economically attractive approach from commercially available benzamide starting material.
- SourceAvailable from: ncbi.nlm.nih.gov[show abstract] [hide abstract]
ABSTRACT: Parallel microscale experimentation was used to develop general conditions for the Suzuki-Miyaura cross-coupling of diversely functionalized primary alkyltrifluoroborates with a variety of aryl chlorides. These conditions were found to be amenable to coupling with aryl bromides, iodides, and triflates as well. The conditions that were previously identified through similar techniques to promote the cross-coupling of secondary alkyltrifluoroborates with aryl chlorides were not optimal for the primary alkyltrifluoroborates, thus demonstrating the value of parallel experimentation to develop novel, substrate specific results.The Journal of Organic Chemistry 04/2009; 74(10):3626-31. · 4.56 Impact Factor
- [show abstract] [hide abstract]
ABSTRACT: Aromatic amide-derived phosphanes (Aphos) are hemilabile P,O-coordinating ligands, which, when combined with a Pd precursor, yield a promising precatalyst system for Suzuki-Miyaura cross-coupling reactions. A focused library of Aphos ligands has been constructed for structural optimization, with the target of improving catalytic efficacy. By using microwave irradiation at accurately regulated temperature, an expeditious and reproducible one-pot synthesis and screening protocol was designed and experimentally validated. The success is based on a unique self-assisted molecular editing (SAME) process in which both the substrate and the product molecules catalyze formation of the product. Thus, starting from a 4-chlorobenzamide-derived Aphos as the substrate, parallel reactions with a selected set of arylboronic acids, in the absence of an added external phosphane ligand to Pd, produced a family of structurally edited Aphos ligands. The resultant reaction mixture containing the new Aphos, the Pd species, and the base could be used for in situ screening of the Aphos efficacy in a reference Suzuki-Miyaura coupling reaction. The structures of all Aphos ligands were characterized by 31P NMR spectroscopy and their catalytic profiles in the reference reaction were evaluated by HPLC analysis. These data allowed the identification of an efficient Aphos ligand, capable of promoting room-temperature Suzuki-Miyaura coupling of unactivated and sterically hindered aryl chlorides with arylboronic acids under mildly basic conditions.Chemistry 07/2008; 14(18):5538-54. · 5.83 Impact Factor
- Chemistry 06/2010; 16(22):6434-7. · 5.93 Impact Factor