Carbonate

Protection :
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ReagentsTimeYield
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Pyr Triphosgene30 - 70 min92-100 %
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Phosgene Pyr30 min100 %Phosgene, PyrPhMe-78 to -23 °C, 30 min, 100%
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NaH CDI20 min81 %NaH, CDIDMFRT, 20 min, 81%
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CDI60 min76 %CDIPhHRT, 60 min, 76%"Also isolated was the desired regioisomer (18 % yield, see next step)."
Deprotection :
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ReagentsTimeYield
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KOH30 min89 %KOHMeOHRT, 30 min, 89%