College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou 325035, China.
Published: May 2022
AI Article Synopsis
Article Abstract
Employing FeCl as a cheap and readily available catalyst, a facile imidization of phosphines with -acyloxyamides is described, affording synthetically useful acyliminophosphoranes with high functional group tolerance. The transformation is easily performed under an air atmosphere at room temperature and could be scaled up to gram scale with a catalyst loading of 1 mol %. The iminophosphoranyl moiety in the product was further utilized as an effective directing group for controllable C(sp)-H bond amidations under Rh(III) catalysis.
We herein report reliable evidence that λ-oxazaphosphetane species are a key intermediate in the transformation of CO and isocyanates through their reaction with -borane-substituted cyclic phosphine imides (BCPIs). We have isolated and fully characterized several λ-oxazaphosphetane species prepared formal [2 + 2] cycloaddition reactions between BCPIs and CO or isocyanates. The transformation of these λ-oxazaphosphetanes retro-ring opening reaction afforded an isocyanate and a carbodiimide from the CO- and isocyanate-derived λ-oxazaphosphetanes.
School of Pharmaceutical Sciences, State Key Laboratory for Macromolecule Drugs and Large-Scale Manufacturing, Liaocheng University, Liaocheng 252059, China.
3,4-disubstituted maleimides find wide applications in various pharmacologically active compounds. This study presents a highly effective approach for synthesizing derivatives of 3,4-disubstituted maleimides through the direct isomerization of α-succinimide-substituted allenoates, followed by a cascade γ'-addition and aryl imines using PR as a catalyst. The resulting series of 3,4-disubstituted maleimides exhibited excellent stereoselectivities, achieving yields of up to 86%.
The trivalent phosphine-catalyzed [4+1] spiro-annulation reaction of allenyl imide and activated methylene cyclocompounds has been developed for the construction of various spiro-2-cyclopenten-1-ones. Oxindoles, 3-isochromanones, and 2-indanones are selected as 1C synthons to capture the in situ-generated bis-electrophilic α,β-unsaturated ketenyl phosphonium intermediate, affording the corresponding monospiro- and bispiro-cyclopentenones in good to excellent yields (≤91%) under mild conditions. The primary attempt at asymmetric catalysis using monophosphine ()-SITCP provides promising enantioselectivity (45% ee).
In these studies, we designed and investigated the potential anticancer activity of five iron(II) cyclopentadienyl complexes bearing different phosphine and phosphite ligands. All complexes were characterized with spectroscopic analysis viz. NMR, FT-IR, ESI-MS, UV-Vis, fluorescence, XRD (for four complexes) and elemental analyses.
Bifunctional ligand-enabled cooperative gold catalysis accelerates nucleophilic attacks and offers a versatile strategy to achieve asymmetric gold catalysis. Distinct from the prior studies employing alkyne/allene as the electrophilic site, this work engages an in situ-generated alkenyl/acyl gold carbene in a ligand-facilitated attack by an alcoholic nucleophile. With an amide-functionalized chiral binaphthylphosphine ligand, γ-alkoxy-α,β-unsaturated imides are formed with excellent enantiomeric excesses.
