Diethyl dicarbonate ketones

A variety of reagents will effect the conversion C(XTH2 - C(XrHC02R the decarbonylation of glyoxalate esters was described above. The most recently described reagent, methyl cyanoformate, reported by Mander and Sethi in 1983, allows the conversion of a preformed lithium enolate to the 3-keto ester in high yield (Scheme 68). Diethyl dicarbonate with potassium hydride in benzene effects the same reaction wiA symmetrical ketones, and with lithium dicyclohexylamide in ether introduces the ethoxycarbonyl group into the a -position of a,3-unsaturated ketones (Scheme 69)."" Diethyl carbon-... 

The readily available 2,3,4,6-fefra-O-benzyl-D-glucopyranose (11) can be used for the synthesis of both nojirimycin (1) and 1-deoxynojirimycin (2) (Schemed).It was treated with EtSH to furnish 12, which was oxidized to the corresponding ketone 13 using TPAP, while the Swern oxidation method failed to produce 13. Treatment of 13 with mercury(ll) salts in the presence of methanol followed by treatment with hydroxylamine hydrochloride in the presence of pyridine afforded the oxime 14 in 73% yield. Treatment of 14 with LiAlH4 in diethyl ether followed by N-protection of the resulting diastereomeric mixture of amines with di-rert-butyl dicarbonate furnished 15 and 16 in 65 and 15% yield, respectively. Pearlman s catalytic hydrogenation of 15 over palladium hydroxide in ethanol followed by treatment of the resulting tetrol with SO2 in water furnished the sulfonic acid 17 in 80% yield. Conversion of 17 into 1 was accomplished by treatment with Dowex 1X2 (OH ) resin. 

Beeswax, white Beeswax, yellow Benzoic, acid Benzyl tiglate y-Bisabolene Brominated vegetable oil 3-Butylidenephthalide Butyloxepanone 3-Butylphthalide Calcium lactate Caramel Castor (Ricinus communis) oil Citronellyl isovalerate Citronellyloxy acetaldehyde p-Cresyl isovalerate p-Cresyl octanoate Crotonic acid p-Cyclocitral p-Damascenone 9-Decenal trans-4-Decenal Diacetyl tartaric acid esters of mono- and diglycerides Diethyl malate Difurfuryl disulfide Dihydroeugenol Dihydro-a-ionone Dihydrojasmone Diisobutyl ketone Diisopropyl disulfide 3,4-Dimethylcyclopentane-1,2-dione Dimethyl dicarbonate 2,5 Dimethyl-3-furanthiol p-a-Dimethylstyrene Diphenyl oxide Ethyl acetate... 

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