Catalytic deacylative alkylations (DaA) of enolcarbonates: Total synthesis of (±)-Crinane
作者:Mrinal K. Das、Abhinay Yadav、Satyajit Majumder、Alakesh Bisai
DOI:10.1016/j.tetlet.2020.152129
日期:2020.7
deacylative allylation (DaA) of enolcarbonates (as pro-nucleophile) of cycloalkanones sharing acyl functionality at C2-position with readily available allylic alcohols (as pro-electrophiles) is disclosed under mild reaction conditions. A wide variety of cycloalkanones with an aromatic ring and allyl group at C-2position (all-carbon quaternary center) are obtained in good to excellent yields (36 examples). The
A Brønsted Acid Catalyst for the Enantioselective Protonation Reaction
作者:Cheol Hong Cheon、Hisashi Yamamoto
DOI:10.1021/ja8041542
日期:2008.7.1
A highly reactive and robust chiral Brønstedacidcatalyst, chiral N-triflyl thiophosphoramide, was developed. The first metal-free Brønstedacid catalyzed enantioselective protonation reaction of silyl enol ethers was demonstrated using this chiral Brønstedacidcatalyst. The catalyst loading could be reduced to 0.05 mol % without any deleterious effect on the enantioselectivity.
Development of a new Lewis base-tolerant chiral LBA and its application to catalytic asymmetric protonation reaction
作者:Cheol Hong Cheon、Tatsushi Imahori、Hisashi Yamamoto
DOI:10.1039/c0cc02492a
日期:——
A new Lewis base-tolerant LBA (LewisAcidAssistedBronstedAcid) derived from La(OTf)(3) and (S)-HOP has been developed as a new chiralBronstedacid. This acid has been successfully applied as a catalyst to asymmetric protonation reactions of silylenolethers of 2-substituted cyclic ketones.
A new strategy using a BINOL derivative as a chiral leaving group and Lewis acid has been developed for enantioselective alkylation of prochiral olefins. (R)-2,2'-Bis[2-(trimethylsilyl)ethoxymethyl]-1,1'-binaphthol is demonstrated to be an effective reagent for enantioselective hydroxymethylation of silyl enol ethers and trisubstituted alkenes. Electrophilic addition to prochiral olefins is accompanied
Enantioselective Protonation of Silyl Enol Ethers Catalyzed by a Chiral Pentacarboxycyclopentadiene-Based Brønsted Acid
作者:Jun Li、Shaoyu An、Chao Yuan、Pingfan Li
DOI:10.1055/s-0037-1611849
日期:2019.7
The enantioselectiveprotonation of silyl enol ethers was realized in the presence of a pentacarboxycyclopenta-1,3-diene-based chiral Bronsted acid catalyst with water as an achiral proton source to give the corresponding α-aryl ketones in good yields and up to 75% ee.