Alfred Hassner (Hebrew: אלפרד הסנר; 11 November 1930 – 27 March 2024) was an Israeli organic chemist.

Alfred Hassner[1][2] was born in Cernăuți and spent World War II in hiding while he lost his father; after the war, he returned to study in Vienna and then immigrated to the USA where he continued his studies.

Hassner was recently Emeritus Professor at Bar Ilan University.

Hassner’s research group has studied: Regioselective additions of pseudohalogens;[5] Stereochemistry of reactions of azides[6] and organic nitrogen functions; Development of catalysts[7] like DMAP for direct esterification of hindered alcohols; Regiochemistry of 3+2 cycloadditions[8] and of 2+2 ketene olefin cycloadditions;[9] Reaction of 3-member-ring iodonium ions and of nitrilium ion[10] intermediates; Reactions of steroids;[11] Organosilanes,[12] Photochemical protection,[13] Medicinal chemistry,[14] electrophilic amination.

Hassner is the author of 320 scientific publications; he was the editor of the scientific series: Advances in Asymmetric Synthesis[22] (JAI press); Small Ring Heterocycles (Wiley);[23] Topics in Heterocyclic Chemistry (Springer).