A Second Generation Formal Synthesis of (−)-Cephalotaxine
作者:Abdul Hameed、Alexander J. Blake、Christopher J. Hayes
DOI:10.1021/jo801540q
日期:2008.10.17
A second generation formal synthesis of the alkaloid (-)-cephalotaxine has been achieved using an alkylidene carbene 1,5-CH insertion reaction to establish a key quaternary stereocenter. The carbene precursor was readily derived from L-proline, and the 1,5-CH insertion reaction was performed under Ohira's conditions using lithiotrimethylsilyldiazomethane (LTDM), which gave the desired spirocyclic product
A Concise, metathesis based approach to construction of the lepadiformine/cylindricine tricyclic framework
作者:Jiwen Zou、Dae Won Cho、Patrick S. Mariano
DOI:10.1016/j.tet.2010.06.027
日期:2010.8
A tandem dienyne metathesis based strategy has been developed for construction of the core tricyclic framework found in the lepadiformine and cylindricine alkaloids. 2-Pentenyl-2-ethynylpyrollidine acrylamide that serves as the starting material for the key ruthenium carbene catalyzed metathesis process is prepared by using a concise route starting with L-proline. (c) 2010 Elsevier Ltd. All rights reserved.
Electroauxiliary-Assisted Sequential Introduction of Two Carbon Nucleophiles on the Same α-Carbon of Nitrogen: Application to the Synthesis of Spiro Compounds
作者:Seiji Suga、Mitsuru Watanabe、Jun-ichi Yoshida
DOI:10.1021/ja028663z
日期:2002.12.1
The sequential introduction of two carbon nucleophiles on the same alpha-carbon of nitrogen by using selective oxidative cleavage of two silyl groups as electroauxilialies has been accomplished. The combination of this expedient transformation and ring-closing metathesis enables reliable and straightforward syntheses of nitrogen-containing spiro compounds, such as cephalotaxine.
Convergency and Divergency as Strategic Elements in Total Synthesis: The Total Synthesis of (−)-Drupacine and the Formal Total Synthesis of (±)-Cephalotaxine, (−)-Cephalotaxine, and (+)-Cephalotaxine
作者:Qi Liu、Eric M. Ferreira、Brian M. Stoltz
DOI:10.1021/jo0710883
日期:2007.9.1
A conciseroute toward the syntheses of (−)-drupacine and (+)- and (−)-cephalotaxine has been developed. The syntheses rely on Pd(II)-catalyzed aerobic oxidative heterocyclization chemistry, which was employed to rapidly construct an important spirocyclic amine intermediate. A dynamic β-elimination/conjugate addition process was strategically applied to complete the first asymmetric total synthesis