Initially, we focused on the coupling of silyl ethers (1) and CO2 derivatives, by using carbamates formed in situ from amines (3) and CO2. This umpolung strategy would give access to a-carbamoyl carbonyl compounds, which are important scaffolds in medicinal chemistry. Reported methods for the synthesis of a-carbamoyl carbonyl compounds from CO2 are very scarce, and typically require the use of high pressures of CO2 and high temperatures. We started by generating carbamate anions by treating amine 3 with NaH under 1 atm of CO2, a modification of a procedure described by Trost for the synthesis of carbonates. A variety of hypervalent iodine reagents (2a-f) were tested (Scheme 1) for the coupling of silyl enol ether 1a-TIPS with carbamate 4. Surprisingly, only those benzoiodoxoles bearing a halide atom on the I(III) (2a, 2c, and 2d) yielded some amounts of acarbamoyl carbonyl product 5a. Of these, it was 1-bromo-3,3-dimethyl-1,3-dihydro-1l 3 [d][1,2]iodaoxole (2c) that gave the best result (27% yield of 5a). Togni reagent 2b, commonly used in radical additions of CF3, left the starting silyl enol ether 1a-TIPS untouched. The use of Koser's reagent 2e led to the formation of by-products, and with phenyl-λ3-iodanediyl diacetate (PIDA) (2f) again the starting enol ether 1a-TIPS was recovered.