Protodeborylation of triorganoboranes

Abstract

Protodeborylation of triorganoboranes, usually carried out under mild reaction conditions using an excess of acetic acid, affords 1,5-dialkyl-3,7- dimethyl-4,8,9-trioxa-2,6-dioxonia-1,5-diboratabicyclo [3.3.1]nona-2,6-dienes OB(R)OC(Me)OB(R)OC(Me)O [1 (R = Et), 2 (R = cyclooctyl)]. Acetoxy(dialkyl) boranes and di(acetoxy)alkylboranes were not formed in an appreciable amount. Compounds 1 and 2 were characterized by NMR spectroscopy (1H, 11B, 13C NMR) in solution, the molecular structure of 2 was determined by X-ray analysis. The gas-phase geometry of 1 was optimized by calculations [B3LYP/6-311+G(d,p) level of theory], and its NMR parameters were also calculated at the same level of theory. © 2008 Verlag der Zeitschrift für Naturforschung.