Dealuminated H–Y zeolites generate, stabilize and catalytically insert carbenes from diazocarbonyl compounds

Abstract

• Simple acid zeolites catalyze the selective generation and insertion reaction of carbenes. • Challenging bonds such as C–C, C–H, O–H, N–H, Si–H and O–O engage in the reaction. • Any metal is not required to perform the reaction. • The solid catalyst can be reused five times without any decrease in final conversion and yields. • A triplet carbene is formed on the isolated acid sites of the zeolite. Carbenes are among the most powerful reactants in organic synthesis, with capacity to insert into a variety of otherwise stable bonds, and generate two new bonds in a straightforward manner. However, the intrinsic instability of such carbenes makes them to be catalytically generated, in–situ, from precursors such as diazocarbonyl compounds, and the catalyst, in turn, also controls the subsequent insertion reaction. The catalyst is generally a metal complex in solution, mainly Cu, Ag or Rh, but also others, including protons in rare cases. Here we show that carbenes are generated, stabilized and inserted into C–C, C–H, O–H, N–H, Si–H and O–O bonds after reacting diazocarbonyl compounds with catalytic amounts of metal–free, commercially available dealuminated H–Y zeolites. These results open the way to design carbene–mediated organic reactions on readily available and reusable catalytic solids without involving metals.

Topics & Concepts