Ir-Catalyzed Asymmetric Total Synthesis of (−)-Communesin F
作者:Xiao Liang、Tian-Yuan Zhang、Xue-Yi Zeng、Yu Zheng、Kun Wei、Yu-Rong Yang
DOI:10.1021/jacs.7b00854
日期:2017.3.8
The first catalytic asymmetrictotalsynthesis of the heptacyclic alkaloid (-)-communesin F is described. A key step features an iridium-catalyzed asymmetric intermolecular cascade cyclization, constructing the lower N,N-aminal-containing CDEF tetracyclic core in one step. Another notable element is the closure of final ring system (A ring) via a facile reduction of a twisted amide and concomitant
描述了七环生物碱 (-)-communesin F 的第一个催化不对称全合成。一个关键步骤是铱催化的不对称分子间级联环化,一步构建含 N,N-氨基的低级 CDEF 四环核心。另一个值得注意的元素是最终环系统(A 环)的闭合,通过轻松还原扭曲的酰胺和由 N,O-半胺醛中间体的甲磺酰化激活的伴随环化。
Catalytic asymmetric formal total syntheses of (+)- and (−)-cycloclavine
We report an expeditious catalytic asymmetric approach to clavine alkaloids via a key Heck cyclization. This reaction sets the formation of vicinal stereocenters with excellent diastereoselectivity. Utilizing the aforementioned strategy, the formal total synthesis of cycloclavine (1) has been achieved via another key late-stage ester-aminolysis of 6.
Under palladium catalysis, Et3B nicely promotes allyl alcohols to undergo C3-selective allylation of indoles and tryptophan; the yields range 75-95%.
Enantioselective Total Synthesis of (+)-Lysergic Acid, (+)-Lysergol, and (+)-Isolysergol by Palladium-Catalyzed Domino Cyclization of Allenes Bearing Amino and Bromoindolyl Groups
Enantioselective total synthesis of the biologically important indole alkaloids (+)-lysergol, (+)-isolysergol, and (+)-lysergic acid is described. Key features of these total synthesis include (1) a facilesynthesis of a chiral 1,3-amino alcohol via the Pd(0)- and In(I)-mediated reductive coupling reaction between l-serine-derived 2-ethynylaziridine and formaldehyde; (2) the Cr(II)/Ni(0)-mediated Nozaki−Hiyama−Kishi
chemo- (C vs. N: >99%; C2 vs. C3: >98%), regio- (linear vs. branch: >99%), and stereo-selectivity (E vs. Z: >99%) and functional group tolerance. The use of water not only provides sustainability by eliminating the need for organic solvent as reaction media but it also activates allylic alcohols via hydrogen bond networking and stabilizes the consequent hydroxide ion (strong solvation effect) resulting
本文报道了在温和条件下使用烯丙醇对 (NH)-吲哚进行“水中”镍催化的化学选择性C 3烯丙基化反应。发现不同的吲哚和烯丙醇与优异的化学-(C 对 N:>99%;C 2 对 C 3:>98%)、区域-(线性对分支:>99%)和立体-相容选择性(E vs. Z:>99%)和官能团耐受性。水的使用不仅通过消除对有机溶剂作为反应介质的需要来提供可持续性,而且还通过活化烯丙醇氢键网络并稳定随后的氢氧根离子(强溶剂化作用),导致容易的氧化加成,并由此形成亲电的 π-烯丙基镍络合物,导致C 3 -烯丙基吲哚。该研究进一步强调了第一个氢键辅助分子间 N → C 烯丙基通过π-烯丙基镍络合迁移,并报告了首次使用烯丙胺作为亲电前体合成烯丙基吲哚。