- Unusual and unexpected reactivity of t-butyl dicarbonate (Boc2O) with alcohols in the presence of magnesium perchlorate. A new and general route to t-butyl ethers
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(Chemical Equation Presented) A new mild method for protecting alcohols as t-butyl ethers is reported. The reaction proceeds with Mg(ClO4) 2 and Boc2O and shows general applicability. The deprotection of t-butyl ethers has also been revisited. Preliminary results indicate the CeCl3·7H2O/Nal system is a very suitable catalyst for their removal.
- Bartoli, Giuseppe,Bosco, Marcella,Locatelli, Manuela,Marcantoni, Enrico,Melchiorre, Paolo,Sambri, Letizia
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p. 427 - 430
(2007/10/03)
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- SYNTHESIS OF AMINO SUGARS VIA ISOXAZOLINES. DL- AND D-LIVIDOSAMINE (2-AMINO-2,3-DIDEOXY-RIBO-HEXOSE) DERIVATIVES FROM 4-VINYL-1,3-DIOXOLANES AND NITROACETALDEHYDE ACETALS
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1,3-Dipolar cycloaddition of nitrile oxides, generated from nitroethanol and nitroacetaldehyde derivatives 3, 21 and 22, respectively, and of benzonitrile oxide to 4-vinyldioxolanes 1,2 gave ca 4:1 erythro/threo mixtures of corresponding isoxazolines.LAH reduction of erytho isoxazolines proceeded with similar (ca4:1) selectivity to furnish protected ribo-amino-polyols 11, 15, 19, DL- and D-lividosamines 31 and 33, respectively, as main products.The DL-lividosamine derivative 33 was obtained pure by crystallization.In the D-series, the corresponding ribo/arabino mixture D-31/D-32 was transformed to the known α-methyl D-lividosaminide D-37.
- Jaeger, Volker,Schohe, Rudolf
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p. 2199 - 2210
(2007/10/02)
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