Abstract: The present invention relates to a process for synthesizing a multifunctional compound, including the reaction of a compound of formula (II) with atmospheric or molecular oxygen, in the presence of at least one aldehyde of formula (III), and optionally in the presence of at least one catalyst or at least one radical initiator; wherein: R10, R20, R30, R40, R50, L2, R60, R7, R8, and R9 are as described in the claims. The invention also relates to the use of these compounds as monomers for the preparation of polyurethane. The invention also relates to the use of these compounds as monomers of polymers or of biopolymers.