Carbanion rearrangements. Collision-induced dissociations of the enolate ion of heptan-4-one

Analysis of triptophenolide and its related compounds from Tripterygium wilfordii Hook.f by electrospray ionization tandem mass spectrometry

“…Previously, Tumas et al have conducted a systematic investigation of the infrared multiple photon (IRMP) photochemically induced decompositions of a series of alkoxide anions a and provided a stepwise mechanism for the formal 1,2-elimination of neutral fragments based on kinetic isotope effects and reactivity patterns, which involving initial heterolytic cleavage to an intermediate anion-ketone complex followed by proton transfer to give the ultimate product (Scheme 4a) [24]. Furthermore, Stringer et al have conducted the collision activated mass experiment of the heptan-4-one enolate ion b, which shows major elimination of methane through stepwise process via a six-center state by application of double isotope labeling technique (Scheme 4b) [25]. Inspired by their works, we proposed that compound A1 (c) might be subjected to the similar process when loss of a molecule of methane.…”

Anionic rearrangements of deprotonated α‐alkoxyvinyltrimethylsilanes in the gas phase

“…Methyl anion migration in 5, could, in principle, form either of the ion complexes 6 and 7, which could decompose to products as shown in Eqns (9)- (12). The methyl group thus migrates either to the methylene carbon or to the silicon of an incipient dimethylsilene (Me,Si=CH,).…”

The Formation of the Neutral Isomers NCCCCO and CCC(O)CN in the Gas Phase from Ionic Precursors: a Joint Experimental and Theoretical Study

“…All experiments were performed with a VG ZAB 2HF two-sector mass spectrometer of BE configuration (B stands for magnetic and E for electric sector), which has been described previously. 12 In summary, precursor anions [NCCCCO] + and [CCC(O)CN] -• were prepared in the chemical ionization (CI) source of the mass spectrometer by R cleavage of [NCCtCCOMe] +• and by the S N 2(Si) reaction between F -(from SF 6 ) and (CH 3 ) 3 Si-CtC-CO-CN. 13 The ions were accelerated to 7 keV translational energy and mass selected by means of the magnet.…”