Catalytic Asymmetric (3 + 3) Cycloaddition of Oxyallyl Zwitterions with α-Diazomethylphosphonates
作者:Yan Liu、Xian Peng、Rui She、Xin Zhou、Yungui Peng
DOI:10.1021/acs.orglett.1c02809
日期:2021.9.17
The unique structure of oxyallyls represents a significant challenge for their catalyticasymmetric applications. Herein, an unprecedented chiral imidodiphosphoric acid-catalytic enantioselective (3 + 3) cycloaddition between oxyallyl zwitterions generated in situ from α-haloketones and α-diazomethylphosphonates was developed. Pharmaceutically interesting chiral pyridazine-4(1H)-ones were obtained
The First Asymmetric Halogen/Metal-Exchange Reaction: Desymmetrization of Alcohols with Enantiotopic Bromoarene Substituents
作者:Daniel Sälinger、Reinhard Brückner
DOI:10.1002/chem.200802488
日期:2009.7.6
Choosy organomagnesium: Prochiral bis(bromoaryl)alcohols were desymmetrized by treatment with iPr2Mg and an enantiopure Li salt. The resulting arylmagnesium intermediate was trapped with electrophiles. Protonolysis and two follow‐up reactions provided the antihistaminic and anticholinergic drug (R)‐orphenadrine (see scheme).
Lowering Inversion Barriers of Buckybowls by Benzannelation of the Rim: Synthesis and Crystal and Molecular Structure of 1,2-Dihydrocyclopenta[<i>b</i>,<i>c</i>]dibenzo[<i>g</i>,<i>m</i>]corannulene
作者:Zbigniew Marcinow、Andrzej Sygula、Arkady Ellern、Peter W. Rabideau
DOI:10.1021/ol016607h
日期:2001.11.1
[structure: see text]. The title compound (3) has been synthesized by a non-pyrolytic route providing a 36% isolated yield in the final step. X-ray crystalstructure determination shows that 3 crystallizes with one solvating molecule of toluene and exhibits slightly lower curvature than the parent cyclopentacorannulene. DFT calculations predict a substantially lower bowl-to-bowl inversion barrier for
Enantioselective Acyloin Rearrangement of Acyclic Aldehydes Catalyzed by Chiral Oxazaborolidinium Ion
作者:Soo Min Cho、Si Yeon Lee、Do Hyun Ryu
DOI:10.1021/acs.orglett.1c00314
日期:2021.2.19
A catalytic enantioselective acyloin rearrangement of acyclic aldehydes to synthesize highly optically active acyloin derivatives is described. In the presence of a chiral oxazaborolidinium ion catalyst, the reaction provided chiral α-hydroxy aryl ketones in high yield (up to 95%) and enantioselectivity (up to 98% ee). In addition, the enantioselective acyloin rearrangement of α,α-dialkyl-α-siloxy