The dissymmetrical chiral bidentate (R)-(+)-1-(diphenylphosphino)-2-(diphenylarsino)propane was prepared stereoselectively via the novel asymmetric hydroarsination reaction between diphenylarsine and diphenyl-1-propenyl-(E)-phosphine using di-mu-chlorobis{(S)-1-[1-(dimethylamino)ethyl]-2-naphthalenyl-C,N}dipalladium(II) as the chiral reaction promoter.