An efficient method for the preparation of 3-sulfonylated 3,3-disubstituted oxindole derivatives has been developed. The protocol involves a base-catalyzed addition of sulfinatesalts to 3-halooxindoles, affording a wide range of 3-sulfonylated 3,3-disubstituted oxindoles in good to excellent yields under mild conditions. A preliminary trial of asymmetric catalytic version was conducted and gave promising
KOH-mediated stereoselective alkylation of 3-bromooxindoles for the synthesis of 3,3′-disubstituted oxindoles with two contiguous all carbon quaternary centres
作者:Manju Devi、Amol P. Jadhav、Ravi P. Singh
DOI:10.1039/d0nj06283a
日期:——
The stereoselectivesynthesis of 3,3′-disubstituted oxindoles having all-carbon quaternary stereocenters has been achieved using KOH as a base with an excellent diastereomeric ratio (98 : 2). The practicability of the present methodology has been validated with the synthesis of a series of substrates in good to excellent yields. The aesthetic simplicity, accessibility, and eco-friendly base (KOH) have
Catalytic Asymmetric Synthesis of Vicinal Quaternary Stereocenters Enabled by Alkylation of α,α-Disubstituted Aldehydes with 3-Bromooxindoles
作者:Long-Jun Dong、Qi Wang、Jing-Feng Zhang、Zhen Li、Dao-Yong Zhu、Xiao-Ming Zhang、Yong-Qiang Tu、Shao-Hua Wang
DOI:10.1021/acs.orglett.4c00700
日期:2024.4.19
An organocatalytic enantioselective alkylation of α,α-disubstituted aldehydes with 3-bromooxindoles is reported. Enantioenriched oxindoles with vicinal quaternary stereocenters are accessed by an asymmetric conjugate addition process of branched aldehydes with o-azaxylylene intermediates (indol-2-ones). Key to the success of highly diastereo- and enantioselective transformations is the combined use
<scp>l</scp>-Amino Acid Based Urea–Tertiary Amine-Catalyzed Chemoselective and Asymmetric Stereoablative Carboxylation of 3-Bromooxindoles with Malonic Acid Half Thioesters
An L-amino acid based urea tertiary amine-catalyzed enantioselective stereoablative carboxylation of 3-bromooxindoles with malonic acid half thioesters (MAHTs) and diverse commercially available carboxylic acids has been developed. A series of valuable 3-substituted 3-hydroxy-2-oxindoles were obtained in high enantioselectivities (up to 93% ee). This chemoselective reaction represents the first example of MAHTs as carboxylating agents.