Asymmetric Route to Pyridines Bearing a Highly Functionalized 2-Alkyl Substituent by Aziridine Ring-Opening Reactions
摘要:
[GRAPHICS]The aziridine prepared from the 2-pyridineimine derived from (S)-valinol underwent ring-opening by attack of nitrogen, sulfur, and oxygen nucleophiles. Complete or prevalent regioselectivity was obtained using cerium trichloride heptahydrate as a catalyst. In some cases, the N-substituent could be removed by an oxidative protocol.
Asymmetric Route to Pyridines Bearing a Highly Functionalized 2-Alkyl Substituent by Aziridine Ring-Opening Reactions
作者:Diego Savoia、Giuseppe Alvaro、Romano Di Fabio、Andrea Gualandi
DOI:10.1021/jo070364a
日期:2007.5.1
[GRAPHICS]The aziridine prepared from the 2-pyridineimine derived from (S)-valinol underwent ring-opening by attack of nitrogen, sulfur, and oxygen nucleophiles. Complete or prevalent regioselectivity was obtained using cerium trichloride heptahydrate as a catalyst. In some cases, the N-substituent could be removed by an oxidative protocol.
Asymmetric Synthesis of 2-(2-Pyridyl)aziridines from 2-Pyridineimines Bearing Stereogenic <i>N</i>-Alkyl Substituents and Regioselective Opening of the Aziridine Ring
作者:Diego Savoia、Giuseppe Alvaro、Romano Di Fabio、Andrea Gualandi、Claudio Fiorelli
DOI:10.1021/jo0614137
日期:2006.12.1
2-pyridinecarboxaldehyde and (S)-valinol, protected as its O-trimethylsilyl ether, gave the 1,2-disubstituted aziridine with good yield and diastereoselectivity. The analogous reaction performed on the imine derived from (S)-valine methyl ester gave the product containing the aziridinering and the α-chloro ketone group coming from the attack of chloromethyllithium to the ester function. Other stereogenic