Le Blanc, Luc M.; Powers, Sean W.; Grossert, J. Stuart; White, Robert L. published the article 《Competing fragmentation processes of β-substituted propanoate ions upon collision induced dissociation》. Keywords: competing fragmentation process beta substituted propanoate ion CID.They researched the compound: 2-Cyano-2-methylpropanoic acid( cas:22426-30-8 ).Name: 2-Cyano-2-methylpropanoic acid. Aromatic heterocyclic compounds can be divided into two categories: single heterocyclic and fused heterocyclic. In addition, there is a lot of other information about this compound (cas:22426-30-8) here.
Rationale : When subjected to collisional activation, gas-phase carboxylate ions typically undergo decarboxylation. However, alternative fragmentation processes dominate when the carboxylate group is located within certain structural motifs. In this work, the fragmentation processes of β-substituted carboxylate ions are characterized to improve correlations between reactivity and structure. Methods : Mass spectra were collected using both ion trap and triple quadrupole mass spectrometers operating in the neg. ion mode; collision induced dissociation (CID) of ions was used to study the relationship between product ions and the structures of their precursor ions. Quantum mech. computations were performed on a full range of reaction geometries at the MP2/6-311++G(2d,p)//B3LYP/6-31++G(2d,p) level of theory. Results : For a series of β-substituted carboxylate ions, a product ion corresponding to the anion of the β-substituent was obtained upon CID. Detailed computations indicated that decarboxylative elimination and at least one other fragmentation mechanism had feasible energetics for the formation of substituent anions differing in their gas-phase basicities. Predicted energetics for anti- and synperiplanar alignments in the transition structures for decarboxylative elimination correlated with the positions of crossover points in breakdown curves acquired for conformationally constrained ions. Conclusions : The feasibility of more than one mechanism was established for the fragmentation of β-substituted propanoates. The contribution of each mechanistic pathway to the formation of the substituent anion was influenced by structural variations and conformational constraints, but mostly depended on the nature of the substituent.
Compounds in my other articles are similar to this one(2-Cyano-2-methylpropanoic acid)Name: 2-Cyano-2-methylpropanoic acid, you can compare them to see their pros and cons in some ways,such as convenient, effective and so on.
Reference:
Chapter 1 An introduction to palladium catalysis,
Palladium/carbon catalyst regeneration and mechanical application method