决明和Prosopis物种的顺式 -2-甲基-6-取代的哌啶-3-醇生物碱很容易通过结合氮杂-Achmatowicz 氧化重排和二氢吡啶酮还原,然后将立体选择性烯丙基硅烷加成到N-磺酰亚胺离子上来制备。还原反应的立体化学结果可归因于假轴取向的2,6-取代基和赤道接近的氢化物试剂之间的空间位阻,这解释了通过氢化物的轴向接近而排他地形成顺式醇。通过催化还原除去( E )-甲基-戊-3-烯酸酯侧链中存在的不饱和度,并将剩余的酯基转化为相应的Weinreb's酰胺。该关键中间体用于合成阿齐米酸、脱氧卡辛、酪氨酸和香料。( S )-N-甲苯磺酰氨基呋喃16的简便制备及其向手性 Achmatowicz 氧化产物18 的转化提供了这些生物碱的正式手性合成。
A new concise stereoselective total synthesis of (+)-azimic acid
作者:Zhi-Hui Lu、Wei-Shan Zhou
DOI:10.1016/s0040-4020(01)81294-1
日期:1993.5
A newconcise stereoselective total synthesis of (+)-azimic acid, which is the immediate precursor of macrocyclic dilactone azimine, has been achieved in eleven steps from (2S,6S)-6-hydroxy-2-methyl-N-tosyl-Δ4-piperidone-3 (5) with a high overall yield (36%).
Total Synthesis of Pyrrolidine and Piperidine Natural Products via TMSOTf-Mediated “5/6-<i>endo-dig</i>” Reductive Hydroamination of Enynyl Amines
作者:Santosh J. Gharpure、Raj K. Patel、Krishna S. Gupta
DOI:10.1021/acs.orglett.3c02115
日期:2023.8.11
acid-mediated 5/6-endo-dig reductive hydroamination cascade of enynyl amines. The brevity of the developed strategy allowed for the collective stereoselective totalsynthesis of various alkaloids, including (±)-pyrrolidine cis-225H, (±)-epi-197B, (±)-epi-225C, the family of (+)-solenopsins and (+)-isosolenopsins, and the formal synthesis of (±)-bgugaine and (+)-azimic acid.
A synthesis of the alkaloid azimic acid has been achieved using double hydroformylation with a single tandem condensation to form the six membered ring. The oxygen substituent was introduced by diastereoselective dihydroxylation, cis to the existing alkyl substituent The methyl substituent was introduced via an iminium ion intermediate under stereoelectronic control. (C) 2013 Elsevier Ltd. All rights reserved.