The palladium-catalyzed cross-coupling of dialkylphosphite with aromatic electrophiles (Hirao coupling) was re-investigated. Some limitations in terms of palladium loadings and substrate reactivity are alleviated with the use of Pd(OAc)(2) complexed to 1,1'-bis(diphenylphosphino) ferrocene (dppf) as a ligand. Various aryl and heteroaryl halides are employed to deliver both known and novel substituted phosphonates. The first examples of aryl chloride couplings are also reported. (C) 2008 Elsevier B.V. All rights reserved.
Photochemical functionalization of diazines: metal-free vinylation and phosphonylation
yields. Csp2-phosphorous bond can also be easily created in a photochemical version of the Arbuzov reaction. With UVA and a stoichiometric amount of trimethyl phosphite, the corresponding phosphonates were isolated in good to high yields. Very interesting selectivities were observed under these mild irradiation conditions. Functionalized substrates can be engaged and the resulting products could be