Large-Scale Synthesis of the Anti-Cancer Marine Natural Product (+)-Discodermolide. Part 2: Synthesis of Fragments C<sub>1</sub><sub>-</sub><sub>6</sub> and C<sub>9-14</sub>
作者:Stuart J. Mickel、Gottfried H. Sedelmeier、Daniel Niederer、Friedrich Schuerch、Dominique Grimler、Guido Koch、Robert Daeffler、Adnan Osmani、Alfred Hirni、Karl Schaer、Remo Gamboni、Andrew Bach、Apurva Chaudhary、Stephen Chen、Weichun Chen、Bin Hu、Christopher T. Jagoe、Hong-Yong Kim、Frederick R. Kinder、Yugang Liu、Yansong Lu、Joseph McKenna、Mahavir Prashad、Timothy M. Ramsey、Oljan Repič、Larry Rogers、Wen-Chung Shieh、Run-Ming Wang、Liladhar Waykole
DOI:10.1021/op0341317
日期:2004.1.1
Kilogram-scale syntheses of fragments C1-6 (6) and C9-14 (4) of (+)-discodermolide from common precursor 3 are described. Improved procedures for each step of both fragments were developed by minimizing or eliminating the formation of byproducts that were isolated and characterized in Smith's synthesis.
Intramolecular Stereoselective Protonation of Aldehyde-Derived Enolates
作者:Anastasie Kena Diba、Claudia Noll、Michael Richter、Marc Timo Gieseler、Markus Kalesse
DOI:10.1002/anie.201004619
日期:2010.11.2
Picking sides: Asymmetric protonation of the titled compounds poses a most significant challenge and has been addressed by taking advantage of internal protonation and subsequent hemiacetal formation to avoid epimerization (see scheme). The substrates employed in these transformations can be easily accessed through a sequence of vinylogous aldol reactions with subsequent conjugate reductions.