作者:Douglas C. Behenna、Justin T. Mohr、Nathaniel H. Sherden、Smaranda C. Marinescu、Andrew M. Harned、Kousuke Tani、Masaki Seto、Sandy Ma、Zoltán Novák、Michael R. Krout、Ryan M. McFadden、Jennifer L. Roizen、John A. Enquist、David E. White、Samantha R. Levine、Krastina V. Petrova、Akihiko Iwashita、Scott C. Virgil、Brian M. Stoltz
DOI:10.1002/chem.201003383
日期:2011.12.9
functions with nearly identical efficiency in terms of yield and enantioselectivity. Catalyst discovery and development, the optimization of reaction conditions, the exploration of reactionscope, and applications in target‐directed synthesis are reported. Experimental observations suggest that these alkylationreactions occur through an unusual inner‐sphere mechanism involving binding of the prochiral
Formal Synthesis of Aspidospermidine via the Intramolecular Cascade Transannular Cyclization
作者:Yu-Rong Yang、Jiu-Zhong Huang、Xiao-Ke Jie、Kun Wei、Hongbin Zhang、Min-Cai Wang
DOI:10.1055/s-0033-1338447
日期:——
aspidospermidine is reported through a novel preparation of Stork's penultimate tricyclic ketone intermediate. The key steps of the synthesis consist of an intramolecular cascade transannular cyclization, triggered by the removal of Boc group, which simultaneously forms the C, D, and E rings of aspidospermidine and conveniently setting up the quaternary stereo-center viadecarboxylative alkylation reaction of the
Palladium-Catalyzed Enantioselective Decarboxylative Allylic Alkylation of Cyclopentanones
作者:Robert A. Craig、Steven A. Loskot、Justin T. Mohr、Douglas C. Behenna、Andrew M. Harned、Brian M. Stoltz
DOI:10.1021/acs.orglett.5b02376
日期:2015.11.6
The first general method for the enantioselective construction of all-carbon quaternary centers on cyclopentanones by enantioselective palladium-catalyzed decarboxylative allylic alkylation is described. Employing the electronically modified (S)-(p-CF3)(3)-t-BuPHOX ligand, alpha-quaternary cyclopentanones were isolated in yields up to >99% with ee's up to 94%. Additionally, in order to facilitate large-scale application of this method, a low catalyst loading protocol was employed, using as little as 0.15 mol % Pd, furnishing the product without any loss in ee.