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

Table 2

Screening of the reaction conditions for the synthesis of the 2-phenyl indole from the N-Boc protected enol phosphate.

Entry	Catalyst	Reaction conditions	Yield (%)
			7	8
1	HT-LDH/Pd (2.0 mol%)	H2O/THF, K2CO3, 80°C, 24 h	40	17
2	HT-LDH/Pd (2.0 mol%)	H2O/THF, K2CO3, 80°C, 48 h	–
3	HT-LDH/Pd (2.0 mol%)	THF, K2CO3, 80°C, 24 h	21	13
4	HT-LDH/Pd (2.0 mol%)	Ethanol, K2CO3, 80°C, 24 h	38	35
5	HT-LDH/Pd (2.0 mol%)	H2O/ethanol (1 : 1), K2CO3, 80°C, 24 h	27	65
6	HT-LDH/Pd (2.0 mol%)	H2O/ethanol (1 : 1), Cs2CO3, 80°C, 24 h	22	48
7	PdNPs (5.0 mol%)	H2O/ethanol (1 : 1), K2CO3, 80°C, 24 h	31	24
8	CP-LDH/Pd (2.0 mol%)	H2O/ethanol (1 : 1), K2CO3, 80°C, 24 h	20	32