Synthesis of a Bench-Stable Manganese(III) Chloride Compound: Coordination Chemistry and Alkene Dichlorination.

The complex [MnCl 3 (OPPh 3 ) 2 ] ( 1 ) is a bench-stable and easily prepared source of MnCl 3 . It is prepared by treating acetonitrile solvated MnCl 3 ( 2 ) with Ph 3 PO and collecting the resulting blue precipitate. 1 is useful in coordination reactions by virtue of the labile Ph 3 PO ligands, and this is demonstrated through the synthesis of {Tpm*}MnCl 3 ( 3 ). In addition, methodologies in synthesis that rely on difficult or cumbersome to prepare solutions of reactive MnCl 3 can be accomplished using 1 instead. This is demonstrated through alkene dichlorinations in a wide range of solvents, open to air, and with good substrate scope. Light-accelerated halogenation and radical sensitive experiments support a radical mechanism involving stepwise Cl-atom transfer(s) from 1 .