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。
Enantioselective Total Synthesis of (+)-Azimine and (+)-Carpaine
作者:Taro Sato、Sakae Aoyagi、Chihiro Kibayashi
DOI:10.1021/ol030088w
日期:2003.10.1
text] The enantioselective total syntheses of (+)-azimine and (+)-carpaine have been developed, starting with (S)-1,2,4-butanetriol as a single source of chirality. The key common feature in these syntheses involves stereoselective intramolecular hetero-Diels-Alder reaction of an acylnitroso compound. The critical macrocyclic dilactonization of the N-Cbz derivatives of azimic acid and carpamic acid
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%).
An Aza-Achmatowicz Approach toward the Hydroxylated Piperidine Alkaloids (±)-Azimic Acid and (±)-Deoxocassine
作者:Michael P. Cassidy、Albert Padwa
DOI:10.1021/ol048326q
日期:2004.10.1
[reaction: see text] The synthesis of several cis-2,3,6-trisubstituted piperidines has been developed employing the aza-Achmatowicz oxidation as the key reaction step. Its usage is illustrated by the facile synthesis of the piperidin-3-ol alkaloids (+/-)-deoxocassine and (+/-)-azimic acid.
Stereospecific route to enantiopure all cis-2,3,6-trisubstituted piperidines. Facile synthesis of (−)-deoxocassine and (+)-azimic acid
作者:Dawei Ma、Nan Ma
DOI:10.1016/s0040-4039(03)00820-7
日期:2003.5
of the enantiopure β-amino esters 10 provides the γ-amnio alcohol 11, which is condensed with 2,4-pentadione to afford 12. Stepwise cyclization of 12 produced the cyclic enamine 13, which is hydrogenated to deliver all cis-2,3,6-trisubstituted piperidine 14. Using this reaction sequence and subsequent Baeyer–Villiger oxidation as the key step (−)-deoxocassine and (+)-azimic acid are synthesized.
A combination of 1, 3-dipolar cycloaddition of Z-nitrone (2) to the chiral dipolarophile (3) and subsequent ring transformation of the resulting adducts (4 and 6) to piperidinol (17) has provided a new practical synthesis of 2, 3, 6-trisubstituted piperidine alkaloid, (+)-azimic acid (1).