Synthesis of B, N, O-containing heterocycles via reaction of an aminoborinium ion with cyclic acetals and ketals

Abstract

Dimethylaminoborinium ion [(CH 3 ) 2 NB Y N(CH 3 ) 2 ] undergoes gas-phase Eberlin reactions (Eberlin MN, Cooks RG. Org. Mass. Spectrom. 1993; 28: 679) with neutral cyclic acetals and ketals. Analogously to trans-acetalization in the condensed phase, this reaction involves initial nucleophilic addition at the borinium cation by the acetal or ketal, followed by a ring-opening/recyclization process with concomitant loss of a neutral carbonyl compound and formation of an ionic B, N, O-containing heterocyclic product. The cyclic nature of the product is strongly suggested by multiple-stage mass spectrometry experiments. The reaction gives relatively higher yields than the corresponding acylium, phosphonium and silylium ion reactions and shows larger influences due to the position of the substituent group in 1,3-dioxolanes. Electronic and steric factors have opposite effects on the reaction efficiency, which is consistent with the proposed mechanism.

Borinium, Borenium, and Boronium Ions: Synthesis, Reactivity, and Applications

“…The cis and trans isomers of 1,2‐cyclopentane diols have different reactivities64, 72 because of their different geometries. Five‐membered acetals and ketals react with the B(OMe) 2 + ion61 and with the much more electron‐rich bis(dimethylamino)borinium cation (B(NMe 2 ) 2 + )62 to effect trans ‐acetalization by the elimination of, for example, acetone. Similar reactivity patterns have been observed in the reactions of these substrates with phosphonium ions such as OP + (OMe) 2 73.…”

Ketalization of phosphonium ions by 1,4-dioxane: Selective detection of the chemical warfare agent simulant DMMP in mixtures using ion/molecule reactions

“…For instance, these transacetalization reactions can be used to characterize functional group in either ionic or neutral reactants, revealing specific structural details or distinguishing them from isomers. The gas phase synthesis of several heterocycles has been performed via related transacetalizations with other gaseous amphoteric cations such as sulfinyl [33,34], silylium [35], and borinium [36,37] ions.…”

Borinium‐, Borenium‐ und Boroniumionen: Synthese, Reaktivität, Anwendung

“…Die cis ‐ und trans ‐Isomere der 1,2‐Cyclopentadiole zeigen wegen ihrer unterschiedlichen Strukturen unterschiedliche Reaktivität 64. 72 Fünfgliedrige Acetale und Ketale reagieren mit dem Dimethoxyboriniumkation61 und auch mit dem deutlich elektronenreicheren Bis(dimethylamino)boroniumkation (B(NMe 2 ) 2 + )62 im Sinne einer trans ‐Acetalisierung durch Eliminierung von z. B. Aceton.…”