作者:Yong Sun Park、Peter Beak
DOI:10.1016/0040-4020(96)00736-3
日期:1996.9
A series of lithiation-substitution reactions at the α and β positions of N-Boc N-alkyl cyclopropyl amines is reported. The cyclopropane ring is the preferred position for lithiation in the N-ethyl and N-methyl derivatives 6 and 7, but the N-allyl and N-benzyl derivatives 8 and 9 undergo lithiation at the methylene groups. Lithiations at β positions of the cyclopropylamine ring are observed if the
据报道,在N -Boc N-烷基环丙基胺的α和β位置发生了一系列锂取代反应。在N-乙基和N-甲基衍生物6和7中,环丙烷环是锂化的优选位置,但是N-烯丙基和N-苄基衍生物8和9在亚甲基处进行锂化。如10、15和21反应所示,如果α位被封端或β位被苯基取代激活,则会观察到环丙胺环β位的锂基化。。α和β锂化均可用于锂化环化反应中,以提供双环螺或内稠合的N- Boc胺15、16和25。用s -BuLi /(-)-天冬氨酸随后用三甲基氯硅烷对N -Boc-4-甲苯磺酰哌啶30进行锂化,得到N -Boc氮杂双环[3.1.0]己烷32,其对映体过量范围为18-55%。两个β-甲氧基甲氧基取代的N - Boc环丙胺18和26可以参与与四氰基乙烯的正式[3 + 2]环加成反应,得到高度取代的环戊烷。