Oxadiazolines are bench-stable diazo precursors, which are activated under UV radiation in the presence of vinylboronic acids and aldehydes to enable a one-step three-component assembly of densely-functionalized homoallylic alcohols. Sub-stitution on all positions of the homoallylic alcohol product were achieved with high functional group tolerance. No catalyst or other additive was required to effect the reaction which proceeds at 20 ℃ over 40 minutes. Imines and indoles were also incorporated, giving access to homoallylic amines.