Ruthenium-NHC-Catalyzed Asymmetric Hydrogenation of Indolizines: Access to Indolizidine Alkaloids
作者:Nuria Ortega、Dan-Tam D. Tang、Slawomir Urban、Dongbing Zhao、Frank Glorius
DOI:10.1002/anie.201302218
日期:2013.9.2
complex serves as the catalyst for the high‐yielding and completely regioselective and asymmetrichydrogenation of substituted indolizines and 1,2,3‐triazolo‐[1,5‐a]pyridines. This method should provide ready access to bicyclic products bearing an N‐bridgehead, a motif appearing in 25–30 % of all naturally occurring alkaloids.
越过N桥!钌/ N-杂环卡宾(NHC)络合物可作为取代吲哚嗪和1,2,3-三唑并[1,5- a ]吡啶的高产率,完全区域选择性和不对称氢化的催化剂。该方法应使带有N桥头的双环产物易于获得,该花环出现在所有天然生物碱的25%至30%中。
Cobalt(II)-based Metalloradical Activation of 2-(Diazomethyl)pyridines for Radical Transannulation and Cyclopropanation
A new catalytic method for the denitrogenative transannulation/cyclopropanation of in‐situ‐generated 2‐(diazomethyl)pyridines is described using a cobalt‐catalyzed radical‐activation mechanism. The method takes advantage of the inherent properties of a CoIII‐carbene radical intermediate and is the first report of denitrogenative transannulation/cyclopropanation by a radical‐activation mechanism, which
Studies on the stereochemistry of nucleophilic additions to tetrahydropyridinium salts. A stereospecific total synthesis of (±)-monomorine I
作者:Robert V. Stevens、Albert W. M. Lee
DOI:10.1039/c39820000102
日期:——
A stereospecific total synthesis of the trail pheromone of the pharaoh ant is described.
描述了法老蚁的尾信息素的立体有择的全合成。
Concise Synthesis of Pyrrolidine and Indolizidine Alkaloids by a Highly Convergent Three‐Component Reaction
作者:Guillaume Lapointe、Kurt Schenk、Philippe Renaud
DOI:10.1002/chem.201003137
日期:2011.3.7
The synthesis of pyrrolidine and indolizidine derivatives through radical carboazidation of alkenes with α‐iodoketones, followed by reductive amination, is described. When properly substituted, further lactamization afforded pyrrolizidinones in good yield. This carboazidation/reductive amination sequence was efficiently applied to the total synthesis of three different simple alkaloids, including (±)‐monomorine
An enantioselective access to (−)-indolizidine alkaloids167B, 209D, 239AB, 195B and (−)-monomorine from a new chiral synthon is described. The use of (S)-3-(Cbz-amino)-4-(tert-butyldimethylsilyloxy)butanal, obtained from l-aspartic acid, has provided efficient access of the indolizidine frame work through a Horner–Wadsworth–Emmons reaction and reductive cyclization as the key steps.