An efficient enantioselective synthesis of cyclic α-aminophosphonates via multicomponent reactions of 2-alkynylbenzaldehydes, amines, and dimethylphosphonate has been developed with the use of a chiral silver spirocyclic phosphate as the catalyst. This protocol provides straightforward access to a series of chiral C1-phosphonylated 1,2-dihydroisoquinoline derivatives with high yields (up to 99%) and high enantioselectivities (up to 94% ee) for a broad substrate scope. The products could be further transformed into densely functionalized compounds and corresponding α-aminophosphonic acids.