Bio‐Inspired Fragmentations: Rapid Assembly of Indolones, 2‐Quinolinones,and (−)‐Goniomitine

Inspired by the biogenetic origin of goniomitine, new synthetic bio‐inspired fragmentation strategies for the synthesis of functionalized 2‐quinolinones and indolones have been developed. Remarkable synthetic efficiency was achieved by telescoping several transformations into one‐pot reactions, allowing for the direct coupling of 2‐alkynyl‐anilines and diazo ketones. The synthetic utility was demonstrated by the 5‐step asymmetric total synthesis of (−)‐goniomitine from 2‐ethyl‐cyclopentanone.     

Selective [3+1] Fragmentations of P4 by “P” Transfer from a Lewis Acid Stabilized [RP4]− Butterfly Anion

Two [3+1] fragmentations of the Lewis acid stabilized bicyclo[1.1.0]tetraphosphabutanide Li[Mes*P₄⋅ BPh₃] (Mes*=2,4,6‐tBu₃C₆H₂) are reported. The reactions proceed by extrusion of a P₁ fragment, induced by either an imidazolium salt or phenylisocyanate, with release of the transient triphosphirene Mes*P₃, which was isolated as a dimer and trapped by 1,3‐cyclohexadiene as a Diels–Alder adduct. DFT quantum chemical computations were used to delineate the reaction mechanisms. These unprecedented pathways grant access to both P₁‐ and P₃‐containing organophosphorus compounds in two simple steps from white phosphorus.     

Synthesis of Nitrile‐Bearing Quaternary Centers by an Equilibrium‐Driven Transnitrilation and Anion‐Relay Strategy

The efficient preparation of nitrile‐containing building blocks is of interest due to their utility as synthetic intermediates and their prevalence in pharmaceuticals. As a result, significant efforts have been made to develop methods to access these motifs which rely on safer and non‐toxic sources of CN. Herein, we report that 2‐methyl‐2‐phenylpropanenitrile is an efficient, non‐toxic, electrophilic CN source for the synthesis of nitrile‐bearing quaternary centers by a thermodynamic transnitrilation and anion‐relay strategy. This one‐pot process leads to nitrile products resulting from the gem‐difunctionalization of alkyl lithium reagents.