Regioselective and Enantioselective Synthesis of β-Indolyl Cyclopentenamides by Chiral Anion Catalysis
作者:Subramani Rajkumar、Jiawen Wang、Sujuan Zheng、Donglei Wang、Xueqian Ye、Xuejiao Li、Qian Peng、Xiaoyu Yang
DOI:10.1002/anie.201807010
日期:2018.10.8
The regioselective and enantioselectivesynthesis of β‐indolyl cyclopentenamides, a versatile chiral building block, by asymmetric addition of indoles to α,β‐unsaturated iminium intermediates has been achieved through chiral anion catalysis. Key to the success of this methodology is the generation of a chiral anion‐paired ketone‐type α,β‐unsaturated iminium intermediate from α‐hydroxy enamides. Preliminary
Enantioselective Functionalization of Enamides at the β‐Carbon Center with Indoles
作者:Mirza A. Saputra、Binod Nepal、Nitin S. Dange、Pu Du、Frank R. Fronczek、Revati Kumar、Rendy Kartika
DOI:10.1002/anie.201808764
日期:2018.11.19
enantioconvergent approach for the functionalization of enamides at the β‐carbon atom, which involves a chiral Brønsted acid induced tautomerization of 2‐amidoallyl into 1‐amidoallyl cations. These putative reactive intermediates were produced by ionization of racemic α‐hydroxy enamides with a chiral Brønsted acid and captured with substituted indoles in a highly regio‐ and enantioselective manner.
Cooperative benzylic–oxyallylic stabilized cations: regioselective construction of α-quaternary centers in ketone-derived compounds
作者:Nitin S. Dange、Jacob R. Stepherson、Caitlan E. Ayala、Frank R. Fronczek、Rendy Kartika
DOI:10.1039/c5sc01914a
日期:——
Herein we describe a direct capture of benzylic–oxyallylic stabilized carbocations with high value nucleophiles towards regioselective construction of α-quaternary centers.
Carbazole Annulation via Cascade Nucleophilic Addition–Cyclization Involving 2-(Silyloxy)pentadienyl Cation
作者:Jacob R. Stepherson、Caitlan E. Ayala、Thomas H. Tugwell、Jeffrey L. Henry、Frank R. Fronczek、Rendy Kartika
DOI:10.1021/acs.orglett.6b01376
日期:2016.6.17
strategy toward the synthesis of highly functionalized carbazoles via 2-(silyloxy)pentadienyl cation intermediates, which were generated upon ionization of vinyl-substituted α-hydroxy silyl enolethers under Brønsted acid catalysis. These electrophilic species were found to readily undergo cascade reactions with substituted indoles to generate carbazole molecular scaffolds in good yields via a sequence of
Brønsted Acid Catalyzed α′-Functionalization of Silylenol Ethers with Indoles
作者:Caitlan E. Ayala、Nitin S. Dange、Frank R. Fronczek、Rendy Kartika
DOI:10.1002/anie.201409758
日期:2015.4.7
formation at the α′‐position of silylenolethers by using catalytic amounts of pyridinium triflate is reported. This chemistry successfully produces, structurally challenging, highly substituted indole‐containing silylenolethers in excellent yields with complete regiocontrol, presumably through silyloxyallyl cation intermediates. Despite the use of Brønstedacid, the silylenolether moiety does not