Pd-allylic substitution mediated synthesis of 25-amino vitamin D3 derivatives

Vitamin D3 analogues with a nitrogen atom linked to C-25 have been synthesized. The key step involves an allylic substitution with 2-nitropropane using catalytic species of Pd(0). This optimized procedure gave the desired compound with complete regioselectivity and high yields and was used for the successful preparation of targeted vitamin D derivatives. The chosen strategy for the construction of the triene unit was totally compatible with the new functional groups.