bis(2-bromoethyl) ether. Subsequent hydrogenation over 5% Rh on alumina in the presence of morpholine unexpectedly stops at the hexahydro derivative 4. Amino alcohol 4 promotes the enantioselective addition of diethylzinc to aldehydes at room temperature in up to 99% enantiomeric excess.
[反应:见正文]
氨基醇4(或其对映体)可通过两个简单步骤制备。用双(2-
溴乙基)醚将商业(1R,2S)-2-
氨基-1,2-二苯基
乙醇二烷基化。随后在吗啉存在下于氧化铝上在Rh上进行超过5%Rh的氢化反应意外地在六氢衍
生物4处停止。
氨基醇4促进了室温下
二乙基锌对醛的对映选择性加成,其对映体过量高达99%。