A chiral N-linked C2-symmetric bidentate phosphoramidite (N-Me-BIPAM) was newly developed for the rhodium-catalyzed enantioselective addition of arylboronicacids to N-sulfonylimines. This ligand achieved high enantioselectivities in a range of 84–99% ee in additions of arylboronicacids to N-tosyl- and N-nosylarylaldimines.
Carvone-Derived P-Stereogenic Phosphines: Design, Synthesis, and Use in Allene–Imine [3 + 2] Annulation
作者:Andrew J. Smaligo、Sriramurthy Vardhineedi、Ohyun Kwon
DOI:10.1021/acscatal.8b01081
日期:2018.6.1
[2.2.1] bicyclic chiral phosphines through straightforward syntheses starting from the natural product carvone. This design rationale prompted the development of an unforeseen C-dealkenylation reaction. We have applied these organocatalysts in the asymmetric syntheses of a bevy of pyrrolines, obtained in high yields and enantioselectivities, including a biologically active small molecule, efsevin.
The potential of β‐alkoxy α‐keto amides as pronucleophiles in the enantioselective Mannich type reaction with p‐nosyl imines is presented. The proper combination of β‐alkoxy α‐keto amides and a squaramide‐based Brønsted basecatalyst produced highly enantioenriched Mannich adducts, which may be transformed into functionalized amino diols.
Straightforward Access to Anthrone Functionalized Benzylic Amines via Organocatalytic 1,2-Addition of Anthrones to Imines at Ambient Temperature
作者:Sumit Das、Arup Bhowmik、Writhabrata Sarkar、Aniket Mishra、Indubhusan Deb
DOI:10.1021/acs.joc.0c02959
日期:2021.3.5
Activation of anthrone via benzylic deprotonation in the presence of triethylamine paves the way for the 1,2-addition reaction with imines to provide the desired functionalized anthrones in good to excellent yields under mild and operationally simple reaction conditions with a broad range of substrate scopes without using any external additives or toxic stoichiometric reagents.
作者:Sobia Tabassum、Oksana Sereda、Peddiahgari Vasu Govardhana Reddy、René Wilhelm
DOI:10.1039/b908899g
日期:——
KHMDS and KOtBu are well established as strong, hindered, non-nucleophilic Brønsted bases. However, in the present work these bases are applied as highly active Lewis base catalysts for the formal [2+2] cycloaddition of ketenes with aldehydes and imines.