Sustainable O-formylation of alcohols using CO2 as C1 building block

GABRIELA GASTELU; JORGE G. URANGA

Venecia

Congreso; Green Chemistry Postgraduate Summer School; 2020

Valorizationof CO2 is receiving a considerable attention in green chemistry as aC1 building block in organic synthesis because it is abundant, non-toxic andrenewable. Its capture and activation are the most challenging step due toits stability and inertness. Borohydride is an interesting reducing agent whichis capable of capture and reduce three molecules of CO2 perreductant molecule in mild conditions. Although H2 shows themost favorable atom economy, borohydride is cheap and stable, and the processdoesn?t need high pressure conditions becoming a less risky methodology. Thereaction of CO2 and borohydride results in triformoxyborohydride, acompound already described as formylating and methylating agent of amines. However, the O-formylation of alcohols from CO2 hasn?t beenwidely explored yet, as only a few examples were described. As alcohols arewidely present in biomass derivatives, the interest of this reaction is basedon the synthesis of value-added products from both, biomass and CO2,carbon renewable sources. In addition, formate group can be use as a protectiveor an activating group for further reactions.    Inthis project, CO2 was activated using NaBH4 through anadaption of a methodology previously described in literature.Triformoxyborohydride (-BH(OCHO)3) was obtained andlately used to formylate different alcohols, which included renewable alcohols.The hole process is described in figure 1. Good to excellent yields wereobtained from the formate esters synthesis.