Zweifache Borylierung von Benzolderivaten mit (Diisoalkylamino)boradiyl‐Einheiten

Abstract

Twofold Borylation of Benzene Derivatives with (Diisoalkylamino)boradiyl Units The reaction of subvalent boron species generated by the defluorination of difluoro(diorganylamino)borane with Na/K alloy in the presence of 1,4‐disubstituted benzene derivatives leads to products which contain two (diorganylamino)boradiyl units and two remaining double bonds which are located on the substituted C atoms. Compounds 5 to 8 exhibit structures based on a 2,8‐diborabicyclo[3,2,1]octa‐3,6‐diene skeleton while 9 shows a skeleton with a 1,3a,4,6a‐tetrahydroborolo[3,2‐b]borole structure. The latter structure corresponds to that of 1 obtained in the same reaction with benzene. The compounds are characterized by elemental analyses and spectroscopically [MS, NMR (1H, 11B, 13C, 15N, 19F, 29Si)]. X‐ray structure analyses are presented for 1, 6, 7, 8, and 9.

Bis(diorganylamino)dihalodiboroxanes as Building Blocks for Boron Heterocycles

“…In 5a , bond lengths of the B 2 O skeleton correspond to those in 3a ; however, the BOB angle (111.2(2)°) is rather small, due to the incorporation of the diboroxane system into the five-membered ring. The B−C distances (1.602(3) and 1.626(5) Å) are comparable to those in other five-membered ring systems containing a boron atom and a conjugated double bond . The five-membered and six-membered (nonaromatic) rings form an envelope conformation with C3 (0.46 Å) and C9b (0.55 Å) folded above the plane formed by the other atoms in the rings.…”

“…The B-C distances (1.602(3) and 1.626(5) Å) are comparable to those in other five-membered ring systems containing a boron atom and a conjugated double bond. 29 The fivemembered and six-membered (nonaromatic) rings form an envelope conformation with C3 (0.46 Å) and C9b (0.55 Å) folded above the plane formed by the other atoms in the rings.…”

Tetracyclic silaheterocycle formed through a pericyclic reaction cascade including a two-fold intramolecular C–C bond activation

“…In this respect, the unprecedented structure of 3 is reminiscent of two-fold borylated products, such as V, that have been obtained from defluorination of difluoro(diorganylamino)boranes with Na/K alloy in the presence of benzene derivatives. 16 While there are no detailed mechanistic data available, the formation of V is thought to proceed via double attack of in situ generated borylenes on the aromatic substrates, in similar fashion as outlined for the formation of 3 in Scheme 3 .…”

Reaktionen von Pyridin-Basen mit Na/K-Legierung und Diorganylaminodifluorboranen / Reactions of Pyridine-Bases with Na/K-Alloy and Diorganylaminodifluoroboranes

“…F2B N (C 3H 7')2 [6,7], F2B N (C 4H 9') 2 [8 ] , F2B N (S iM es) 2 [ 9 ] Die Darstellung von Di-s-butylaminodifluorboran (6) A uch der Versuch, die beiden Substanzen durch K ristallisation aus «-H exan oder säulenchrom ato graphisch zu trennen (Füllung: A lum inium oxid, aktiv, n eutral m it E t20 /H e x a n als Lösungsm ittel), …”