Amine Protection/α-Activation with the<i>tert</i>-Butoxythiocarbonyl Group: Application to Azetidine Lithiation–Electrophilic Substitution
作者:David M. Hodgson、Claire L. Mortimer、Jeffrey M. McKenna
DOI:10.1021/ol503441d
日期:2015.1.16
tert-Butoxythiocarbonyl (Botc), the long-neglected thiocarbonyl analogue of Boc, facilitates (unlike its alkoxycarbonyl cousin) α-lithiation and electrophile incorporation on N-Botc-azetidine. N,N,N′,N′-endo,endo-Tetramethyl-2,5-diaminonorbornane proved optimal as a chiral ligand, generating adducts with er up to 92:8. Facile deprotection, under conditions that left the corresponding N-Boc systems
叔丁氧基硫代羰基(Botc)是Boc长期被忽视的硫代羰基类似物,可促进(不同于其烷氧基羰基表亲)在N -Botc-氮杂环丁烷上的α-锂化和亲电试剂结合。Ñ,Ñ,Ñ ',Ñ ' -内,内切-四甲基-2,5- diaminonorbornane证明最佳作为手性配位体,生成具有呃加合物高达92:8。使用TFA或通过在乙醇中热解,可以在保持相应的N -Boc系统完整的条件下进行简便的脱保护。