Interrogating Pd(II) Anion Metathesis Using a Bifunctional Chemical Probe: A Transmetalation Switch
作者:John J. Molloy、Ciaran P. Seath、Matthew J. West、Calum McLaughlin、Neal J. Fazakerley、Alan R. Kennedy、David J. Nelson、Allan J. B. Watson
DOI:10.1021/jacs.7b11180
日期:2018.1.10
Ligand metathesis of Pd(II) complexes is mechanistically essential for cross-coupling. We present a study of halide→OH anion metathesis of (Ar)PdII complexes using vinylBPin as a bifunctional chemical probe with Pd(II)-dependent cross-coupling pathways. We identify the variables that profoundly impact this event and allow control to be leveraged. This then allows control of cross-coupling pathways
nickel-catalyzed vinylation of 2-azaallyl anions is advanced for the first time. This method affords diverse vinyl aryl methyl amines with high enantioselectivities, which are frequently occurring scaffolds in natural products and medications. This C–H functionalization method can also be extended to the synthesis of enantioenriched 1,3-diamine derivatives by employing suitably elaborated vinyl bromides.
Cascade reactions are an important strategy in reaction design, allowing streamlining of chemical synthesis. Here we report a cascade Suzuki–Miyaura/Diels–Alder reaction, employing vinyl Bpin as a bifunctional reagent in two distinct roles: as an organoboron nucleophile for cross-coupling and as a Diels–Alder dienophile. Merging these two reactionsenables a rapid and operationally simple synthesis
SUBSTITUTED INTERNAL VINYL-BORONIC ACIDS AND BORONIC ACID DERIVATIVES
申请人:Math Shivanand K.
公开号:US20120041193A1
公开(公告)日:2012-02-16
Disclosed herein are vinyl-bromides, vinyl-boronic acids and vinyl-boronic acid derivatives useful as synthetic intermediates for the preparation of therapeutic agents. Also disclosed are methods of synthesis of vinyl-bromides, vinyl-boronic acids and vinyl-boronic acid derivatives.
Evaluation of Amino Substituents as Nucleofugal Controllers of Regioselectivity and as Chelate Modulators of Stereoselectivity in Squarate Ester Cascades
作者:Leo A. Paquette、Lung Huang Kuo、Jinsung Tae
DOI:10.1021/jo9722919
日期:1998.3.1
The tandem addition of an alkenyllithium reagent and a 2-lithioallylamine to squarate esters has been systematically examined. The effect of the sequencing of this twofold addition has been investigated. The extent to which the amino group is eliminated was found to be dependent on the structural features of the companion nucleophile. Also assessed was the comparative ease with which the amino and methoxy groups experience competitive beta-elimination from the highly reactive, medium-ring dianionic intermediates. Attempts were made to curtail the level of competing 1,4-addition, and success was achieved by increasing the effective size of the O-alkyl groups in the squarate ester. The highly stereocontrolled transformations described represent a notably direct means for producing highly fused polycyclic compounds, Mechanistic considerations sm rounding these reactions, which are characterized by an impressive enhancement of molecular scaffolding, are discussed.