This work describes our studies on the functionalization at C11 of CD-ring fragments of vitamin D3 using organocopper reagents. As an application, an efficient, convergent synthesis of 11α-[3, 3-(dimethoxy) propyl] calcitriol analogue 2, which may be useful for the construction of affinity columns for the purification of 1α, 25-(OH) 2-vitamin D3 receptors, is described.