Recognition of Cyclic, Acyclic, Exocyclic, and Spiro Acetals via Structurally Diagnostic Ion/Molecule Reactions with the (CH3)2N-C+O Acylium Ion
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- 作者：Mario Benassi ; Luiz Alberto B. Moraes ; Liliane G. Cabrini ; Luiz Carlos Dias ; Andrea M. Aguilar ; Gilberto A. Romeiro ; Livia S. Eberlin ; Marcos N. Eberlin
- 刊名：Journal of Organic Chemistry
- 出版年：2008
- 出版时间：July 18, 2008
- 年：2008
- 卷：73
- 期：14
- 页码：5549 - 5557
- 全文大小：717K
- 年卷期：v.73,no.14(July 18, 2008)
- ISSN：1520-6904
文摘
Reactions of the model acylium ion (CH3)2N-C+
O with acyclic, exocyclic, and spiro acetals of the general formula R1O-CR3R4-OR2 were systematically evaluated via pentaquadrupole mass spectrometry. Characteristic intrinsic reactivities were observed for each of these classes of acetals. The two most common reactions observed were hydride and alkoxy anion [R1O− and R2O−] abstraction. Other specific reactions were also observed: (a) a secondary polar [4+ + 2] cycloaddition for acetals bearing α,β-unsaturated R3 or R4 substituents and (b) OH− abstraction for exocyclic and spiro acetals. These structurally diagnostic reactions, in conjunction with others observed previously for cyclic acetals, are shown to reveal the class of the acetal molecule and its ring type and substituents and to permit their recognition and distinction from other classes of isomeric molecules.
O with acyclic, exocyclic, and spiro acetals of the general formula R1O-CR3R4-OR2 were systematically evaluated via pentaquadrupole mass spectrometry. Characteristic intrinsic reactivities were observed for each of these classes of acetals. The two most common reactions observed were hydride and alkoxy anion [R1O− and R2O−] abstraction. Other specific reactions were also observed: (a) a secondary polar [4+ + 2] cycloaddition for acetals bearing α,β-unsaturated R3 or R4 substituents and (b) OH− abstraction for exocyclic and spiro acetals. These structurally diagnostic reactions, in conjunction with others observed previously for cyclic acetals, are shown to reveal the class of the acetal molecule and its ring type and substituents and to permit their recognition and distinction from other classes of isomeric molecules.