Reaktionen von Buten‐(3)‐ylaminen mit Boranen

Abstract

rnEs wurden die Reaktionen von Buten-(3)-ylamin und N-Methyl-buten-(3)-ylamin mit verschiedenen Boranen, darunter auch Alkyl(Ary1)-halogenborane, untersucht. Mit BH3 und Chlorboranen wurden mit Buten-(3)-ylamin nur Borazolderivate erhalten, mit N-Methylbuten-(3)-ylamin dagegen Borazenderivate, darunter das N-Methyl-tetrahydro-borazaren. Reactions of 3-Butenylamines with BoranesThe reactions of 3-butenylamine and N-methyl-3-butenylamine with different boranes, also with alkyl(ary1)-halogenoboranes, are reported. BH3 and chloroboranes and 3-butenylamine give only borazine derivatives. With N-methyl-3-butenylamine result borazene derivatives, so the N-methyl-tetrahydroborazarene.Im 2.1-Borazaren (1.2-Dihydro-1.2-azaborin) (1) liegt ein Benzolring vor, in dem eine C-C-Gruppe durch die isoelektronische B -N-Gruppe ersetzt ist. An diesem Ring IieRe sich am einfachsten der EinfluB der BN-Gruppe auf das Ringsystem untersuchen. Trotz zahlreicher Versuche gelang bisher nur die einwandfreie Charakterisierung von zwei einfachen Borazarenderivaten, 2 2 ) und 33.4).

The Synthesis, Characterization and Dehydrogenation of Sigma‐Complexes of BN‐Cyclohexanes

“…[9] Compound 2 is, to our knowledge, unreported in the open literature as an isolated compound [29] while compound 3 was originally reported by Wille and Goubeau in 1972. [30] We have isolated compounds 2 and 3 (see Experimental) as an analytically pure powder or liquid, respectively (Scheme 3). The 11 B and 1 H B–H NMR chemical shifts for these three compounds are also given for later comparison with their coordination complexes.…”

“…20 mol%) results in the slow (72 hrs, TOF ~0.07 hr −1 , sealed NMR tube) dehydrocoupling to form the final amino–borane derived tricyclic borazine product [BNC 4 H 8 ] 3 6 [δ 34.5, s; lit. 34.8, C 6 D 6 ], [9, 30] (Scheme 5). Inspection of the 11 B NMR spectrum after 2 hrs shows compound 1 and a significant proportion of a new signal assigned to the new monomeric amino–borane HBNHC 4 H 8 , 7 [δ 41.1, d, J (BH) 124 Hz].…”

“…Compound 8 was initially reported by Wille and Goubeau, [30] and has been independently prepared by intramolecular hydroboration of the N -methylhomoallylamine-borane adduct and subsequent one-pot thermal dehydrogenation (see Experimental section). Compound 8 does not cyclize and remains monomeric in solution, as evidenced by a characteristic down–field chemical shift in the 11 B NMR spectrum δ 40.8 [ J (BH) 125 Hz], very similar to 7 .…”

“…[19, 20] As these are sealed conditions, inhibition by H 2 may well be occurring complicating a detailed kinetic analysis, as observed previously for Rh–systems, [20, 70] Unfortunately we have been unable to reliably measure the rate in an open system (under Ar) due to partial decomposition of 8 upon sampling. [30] …”

“…[30] In a glovebox, a 300 mL pressure vessel was charged with tetrahydrofuran (100 mL) and N,N- dimethylhomoallylamine* (3.00 g, 30.3 mmol, 1 equiv). Borane-tetrahydrofuran solution (36 mL, 1 M in THF, 36 mmol, 1.2 equiv) was added dropwise.…”