A Catalytic Synthesis of Aziridines without the Usual Byproducts
作者:Michael Mayer、Arindam Mazumdar、Zheng Xue
DOI:10.1055/s-2007-984872
日期:——
Complementary to existing routes, the Lewis acid catalyzed reactions of phenyldiazomethane with α-imino esters selectively produce cis-aziridine-2-carboxylates without competitive formation of enamino ester or carbene dimer byproducts.
Vaulted Biaryls in Catalysis: A Structure-Activity Relationship Guided Tour of the Immanent Domain of the VANOL Ligand
作者:Yong Guan、Zhensheng Ding、William D. Wulff
DOI:10.1002/chem.201302451
日期:2013.11.11
anion (boroxinate) that is assembled in situ from three equivalents of B(OPh)3 and one of the VANOLligand by a molecule of substrate. The substrates are bound to the boroxinate by H bonds to oxygen atoms O1–O3. The effects of introducing substituents at each position of the naphthalene core of the VANOLligand are systematically investigated in an aziridination reaction. Substituents in the 4,4′‐ and
Scalable Syntheses of the Vaulted Biaryl Ligands VAPOL and VANOL via the Cycloaddition/Electrocyclization Cascade
作者:Zhensheng Ding、Wynter E. G. Osminski、Hong Ren、William D. Wulff
DOI:10.1021/op200088b
日期:2011.9.16
straightforward, inexpensive, efficient, and amenable to large-scale preparation of the ligands since minimum chromatographic purification is required. The key step in each synthesis is a cycloaddition/electrocyclic ring-opening/electrocyclic ring closure/tautomerization cascade that provides a direct one-step route to the monomers from which each ligand is prepared. Improved phenol coupling protocols
Direct Access to <i>N</i>-H-Aziridines from Asymmetric Catalytic Aziridination with Borate Catalysts Derived from Vaulted Binaphthol and Vaulted Biphenanthrol Ligands
作者:Zhenjie Lu、Yu Zhang、William D. Wulff
DOI:10.1021/ja069371r
日期:2007.6.6
The asymmetriccatalyticaziridination reaction (AZ reaction) of N-dianisylmethylimines (N-DAM-imines) with ethyl diazoacetate is developed with chiral catalysts preparedfrom triphenylborate and both the vaulted binaphthol (VANOL) and vaulted biphenanthrol (VAPOL) ligands. Catalysts derived from both ligands were equally effective in terms of asymmetric induction, but the VANOL catalyst was slightly
Catalytic Asymmetric Aziridination with Borate Catalysts Derived from VANOL and VAPOL Ligands: Scope and Mechanistic Studies
作者:Yu Zhang、Aman Desai、Zhenjie Lu、Gang Hu、Zhensheng Ding、William D. Wulff
DOI:10.1002/chem.200701558
日期:2008.4.18
An extended study of the scope and mechanism of the catalyticasymmetricaziridination of imines with ethyl diazoacetate mediated by catalysts preparedfrom the VANOL and VAPOL ligands and triphenylborate is described. Nonlinear studies with scalemic VANOL and VAPOL reveal an essentially linear relationship between the optical purity of the ligand and the product suggesting that the catalyst incorporates