THP醚引入到一個手性分子的結(jié)果是形成了一個非對映體，因為在四氫吡喃環(huán)上新增了一個手性中心。（有時它會使NMR譜的表達(dá)有點(diǎn)困難）。盡管如此，它仍是有機(jī)合成中一個非常有用的保護(hù)基團(tuán)，它的成本低，易于分離，對大多數(shù)非質(zhì)子酸試劑有一定的穩(wěn)定性，易于純化。通常情況下，幾乎任何酸性試劑或任何可以在原位產(chǎn)生酸的試劑都可被用來引入THP基團(tuán)。
THP(2-四氫吡喃)保護(hù)羥基示例(J.Org.Chem.1977,42,3772)
To a solution of 1 (1.5 g,3.5mmol) in CH2Cl2 (10 mL) at 22-24oC wasadded 3,4- dihydro-2H-pyran (0.479 mL, 0.442 g, 5.25mmol) and PPTs (20 mg, 0.08mmol). The solution wasstirred at 22-24oC for 1 h and diluted with a 100-mL solution of(1:1) diethyl ether and ethyl acetate. The organic layer was separated, washed with H2O(3 ′ 100mL), and the residuewas chromatographed, eluting with hexane/ethyl acetate (20:1) to give the THPether 2 as clear oil (1.75 g, 97%).
THP (2-四氫吡喃)脫保護(hù)示例(J.Org.Chem.1977,42,3772)
To an ethanol solution (30 mL) of THP ether 1 (1.87 g, 5mmol) was added PPTS (20 mg,0.08mmol) in one portion. The solution was refluxed for 1 h, cooled to 22-24oC,and diluted with a mixture of diethyl ether (100 mL) and H2O (200mL). The organic layer was washed with H2O (2 ′ 100mL), dried over Na2SO4and concentrated in vacuo. The residue was purified by chromatography onsilica gel, eluting with hexane/ethyl acetate (3:1) to give 2 (1.36 g, 94%) as clear oil.
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