Sodium Carbonate → tert-butyl-N-(2-ethoxyphenyl)carbamate

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Reaction Steps

In a 500 ml three-necked flask under an argon atmosphere, 8 g (23.8 mmol, 1.7 eq) of tert-butyl-N-{4-[allyl(dimethyl)silyl]-2-ethoxyphenyl}carbamate 7 is mixed with 100 ml of anhydrous THF. Then 42.8 ml (21.4 mmol, 1.5 eq) of 0.5 M 9-BBN is added in anhydrous THF. The reaction is allowed to progress at room temperature and under argon for 4 hours. Then 0.5 g (0.42 mmol, 3% eq) of Pd(PPh3)4, 12 ml (1.7 eq) of an aqueous 2 M Na2CO3 solution, and 3.5 g (14 mmol) of bromopolystyrene resin (substituted 4 mmol/g) is added. The flask is wrapped in a sheet of aluminium foil and the THF is heated under a reflux condenser. After 40 hours, 0.5 g (0.42 mmol, 3% eq) of Pd(PPh3)4 catalyst is added and the reaction of THF under a reflux condenser for 24 hours is continued. The mixture is cooled to room temperature, then allowed to settle before filtering the resin on a Buchner funnel. The resin is washed successively with THF (4×40 ml), a 1% solution of diethyldithiocarbamic acid sodium salt in DMF (4×40 ml), a 1:1 mixture of THF/H2O (4×40 ml), then H2O (2×40 ml), MeOH (2×40 ml), DMF (2×40 ml), MeOH (2×40 ml), 3×[3×40 ml CH2Cl2, 3×40 ml MeOH] and, lastly, dried under vacuum (dessicator). 5.86 g of a light orange powder (yield: 80%) is obtained.

Provenance & Evidence