NHCs Catalyzed Hydrophosphonylation of 𝜶-Ketoesters and 𝜶-Trifluoromethyl Ketones

Table 1

Screening of reaction conditions^a.

Entry	NHC	Solvent	Yield (%)^b
1	1	DCM	99
2	2, Cs2CO3 (10 mol%)	DCM	72
3	2, DBU (10 mol%)	DCM	78
4	3, DBU (10 mol%)	DCM	67
5	4a, Et3N (10 mol%)	DCM	79
6	4b, Et3N (10 mol%)	DCM	52
7	5, Et3N (10 mol%)	DCM	75
8	1	toluene	77
9	1	THF	85
10	1	Et2O	78
11^c	1	DCM	65
12	No catalyst	DCM	/

aReaction condition: 6a (1.5 equiv), 7a (1.0 equiv), NHC (10 mol%), 0.15 mol L⁻¹ of 7a, and room temperature.
^bIsolated yield.
^cUsing 5 mol% NHC 1 (IPr).