Study on Nanocomposites between PdNPs and Layered Double Hydroxides for Challenging Organometallic Catalysis

A new catalytic approach for the C-O activation of enol phosphates based on a palladium supported on layered-double hydroxide is demonstrated. Hydrothermally treated LDH containing Pd(0) gave the best catalytic results.  In particular, two different ketene aminal phosphates were used as models to study the synthesis of \(\alpha\)-phenyl enecarbamates N-Boc/ CBz under the Suzuki-Miyaura conditions. Importantly, the Boc substituted o-brominated enol phosphate was quite stable under the catalytic conditions when compared to the CBz counterpart. The use of an ortho-bromo aniline as precursor allowed the synthesis of the 2-phenyl indole through an arylation/ Heck cyclization in moderate yields. Catalyst reusability enabled the synthesis of the heterocycle in moderate yields for four consecutive runs.