Regioselective and Stereoselective Copper(I)-Promoted Allylation and Conjugate Addition of <i>N</i>-Boc-2-lithiopyrrolidine and <i>N</i>-Boc-2-lithiopiperidine
作者:Iain Coldham、Daniele Leonori
DOI:10.1021/jo100415x
日期:2010.6.18
regioselectively (SN2 mechanism). Addition to an enone or α,β-unsaturated ester occurs by 1,4-addition. Asymmetric deprotonation of N-Boc-pyrrolidine or dynamic resolution in the presence of a chiral ligand of N-Boc-2-lithiopiperidine followed by the zinc/copper chemistry was successful and gave the allylated pyrrolidine and piperidine products with good enantioselectivity, although use of the copper iodide
铜盐已被筛选的转移金属化和电淬火ñ -叔丁氧羰基-2- lithiopyrrolidine(Ñ -Boc-2- lithiopyrrolidine)和Ñ -Boc-2- lithiopiperidine,通过去质子化而形成Ñ -Boc -吡咯烷和ñ - Boc-哌啶分别。然后,用氯化锌(溶解了氯化锂)进行重金属化,然后进行烯丙基化,生成区域异构体的混合物(S N 2和S N 2'产物),而用碘化铜·TMEDA进行重金属化,则区域选择性地进行烯丙基化(S N2机制)。通过1,4-加成发生烯键或α,β-不饱和酯的加成。N -Boc-吡咯烷的不对称去质子化或在N -Boc-2-lithiopiperidine的手性配体存在下的动态拆分以及随后的锌/铜化学反应是成功的,尽管使用了N -Boc-2-lithiopiperidine的手性配体,但烯丙基化的吡咯烷和哌啶产物具有良好的对映选择性碘化铜的化
Stereoselective Coupling of <i>N</i>-<i>tert</i>-Butanesulfinyl Aldimines and β-Keto Acids: Access to β-Amino Ketones
作者:Alejandro Lahosa、Tatiana Soler、Ana Arrieta、Fernando P. Cossío、Francisco Foubelo、Miguel Yus
DOI:10.1021/acs.joc.7b01178
日期:2017.7.21
The reaction of chiral N-tert-butanesulfinyl aldimines with beta-keto acids under basic conditions at room temperature proceeds with high levels of diastereocontrol, leading to beta-amino ketones in high yields. Based on DFT calculations, an eight-membered cyclic transition state involving coordination of the lithium atom to the oxygens of carboxylate and sulfinyl units was proposed, being in agreement with the observed experimental diastereomeric ratios. The synthesis of the piperidine alkaloid (-)-pelletierine was successfully undertaken in order to demonstrate the utility of this methodology.
Straightforward Access to Enantioenriched 2-Allylpiperidine: Application to the Synthesis of Alkaloids
作者:Irene Bosque、José C. González-Gómez、Francisco Foubelo、Miguel Yus
DOI:10.1021/jo202211u
日期:2012.1.6
requires only two synthetic operations with one-column chromatography and is readily scaled up. The versatility of these chiral building blocks was exemplified by the total or formal synthesis of some natural and unnatural alkaloids.