Chiral organophosphorus compounds are highly useful in biochemistry,organic synthesis,and asymmetriccatalysis.However,successful enantioselective preparation of these compounds via metal-catalyzed asymmetricaddition of H-P bonds to alkenes is limited.Unlike other H-phosphonates,which can not undergo metal-catalyzedaddition to alkenes,a five-membered cyclic H-phosphonate,4,4,5,5-tetramethyl-1,3,2- dioxaphospholane 2-oxide1a adds smoothly to alkenes to afford the adducts in high yields.1 After ligand evaluation using various mono- anddiphosphine ligands,we found that Josiphos ligands 2 are the best for the palladium-catalyzed asymmetrichydrophosphorylation of norbornene with 1a.By condition optimization,corresponding phosphonates can beobtained in high yield and high enantioselectivity.2 The reaction was applicable to substituted norbornenes andother five-membered cyclic H-phosphonates.In addition,the Josiphos ligand is also a better ligand than(R,S)-binaphos3 for the asymmetric addition of 1a to styrene.Thus,using ligand 2e the branched adduct wasobtained in high regioselectively (＞94％) with 72.5％ ee.