N-Allylideneamines 1a, b were prepared from acrolein and diphenylethyl or trityl amine in the presence of Ti(OEt)4. Double nucleophilicaddition of various ketene silyl (thio)acetals and trimethylsilyl cyanide to these imines proceeded efficiently to give, after workup with TFA, homoglutamic acid derivatives 3 and valerolactam 5.
Iridium-Catalyzed Enantioselective Allylic Substitution of Aliphatic Esters with Silyl Ketene Acetals as the Ester Enolates
作者:Xingyu Jiang、John F. Hartwig
DOI:10.1002/anie.201704354
日期:2017.7.17
Enantioselective allylic substitution with enolates derived from aliphatic esters under mild conditions remains challenging. Herein we report iridium‐catalyzed enantioselective allylation reactions of silyl ketene acetals, the silicon enolates of esters, to form products containing a quaternary carbon atom at the nucleophile moiety and a tertiary carbon atom at the electrophile moiety. Under relatively
While iminium salts generated by the oxidation of amino ketene silyl acetals show intriguing reactivities to give useful γ-oxo-α-amino esters via reactions with silyl enol ethers in good yields, new iminium salts are also prepared by the oxidation of amino silyl enol ethers. They undergo facile addition reaction with various nucleophiles to give α-amino ketone derivatives in good yields.
Iminium salts generated by the oxidation of amino ketene silyl acetals underwent a facile Mannichreaction with another ketene silyl acetal to give aspartic acid derivatives in good yields. The dia...