Palladium on Layered Double Hydroxide: A Heterogeneous System for the Enol Phosphate Carbon-Oxygen Bond Activation in Aqueous Media

Table 1

Screening of the reaction conditions for the synthesis of the -phenyl-enecarbamates from the N-CBz protected enol phosphates.

Entry	Ar	Catalyst	Reaction conditions	Yield (%)
1	4-OCH3	HT-LDH/Pd (1.0 mol%)	H2O/EtOH, 75–80°C	–
2	4-OCH3	HT-LDH/Pd (1.0 mol%)	H2O/EtOH, K2CO3, 75–80°C	41%
3	4-OCH3	HT-LDH/Pd (2.0 mol%)	H2O/EtOH, K2CO3, 75–80°C	50%
4	4-OCH3	HT-LDH/Pd (2.0 mol%)	H2O, K2CO3, 75–80°C	–
5	4-OCH3	HT-LDH/Pd (2.0 mol%)	EtOH, K2CO3, 75–80°C	–
6	4-OCH3	HT-LDH/Pd (2.0 mol%)	H2O/THF, K2CO3, 75–80°C	72%
7	4-OCH3	CP-LDH/Pd (2.0 mol%)	H2O/THF, K2CO3, 75–80°C	39%
8	4-OCH3	Pd nanoparticles (2.0 mol%)	H2O/THF, K2CO3, 75–80°C	35%
9	4-OCH3	Pd nanoparticles (5.0 mol%)	H2O/THF, K2CO3, 75–80°C	40%
10	4-OCH3	Na2PdCl4 (2.0 mol%)	H2O/THF, K2CO3, 75–80°C	–
11	2-Br	HT-LDH/Pd (2.0 mol%)	H2O/THF, K2CO3, 75–80°C	n.d.