作者:Rudolf O. Duthaler、Bernhard Wyss
DOI:10.1002/ejoc.201100247
日期:2011.8
reagent couple trimethylsilyl halides/phenol selectively cleaves the N-Boc group, LiOH/H2O2 transforms the thiol lactones into lactones by an unknown mechanism, and, subsequently, also cleaves the acetonide affording N-Boc-protected D-amino acids without loss of optical activity. This sequence tolerates unsaturated residues with sensitive allylic functions. In some cases, double bond isomerization is, however
自然构造的半胱氨酸通过对应于丝氨酸衍生的加纳醛的 4-甲醛转化为 4-取代的噻唑烷。关键的转化是通过 1O2 氧化转化为 5-噻唑烷酮,并在原位乙酰化条件下裂解初级 5-氢过氧化物。鉴于试剂对三甲基硅烷基卤化物/苯酚选择性地裂解 N-Boc 基团,而 LiOH/H2O2 通过未知机制将硫醇内酯转化为内酯,随后也裂解丙酮化物,提供 N-Boc 保护的 D-氨基酸而不会丢失的光学活性。该序列耐受具有敏感烯丙基功能的不饱和残基。然而,在某些情况下,观察到双键异构化。噻唑烷中间体可以用 3-硝基-2-吡啶亚磺酰氯裂解,