Chelate-Stabilized 1,3-Bis(acyloxy)-1,3-diethyldiboroxanes from Triethylboroxin and Carboxylic Acid Anhydrides['"]Triethylboroxin (A) reacts with carboxylic acid anhydrides (RC0)20 [R = Me: la; Et: lb; tBu: Id; Ph: l e ] with various rates to give high yields of the 3,7-dialkyl-lV5-diethyl-4,8,9trioxa-2,6-dioxonia-1,5-diboratabicyclo[ 3.3.l]nona-2,6-dienes dB(Et)OC(R)Ok(Et)OC(R)O (2) [R = Me: 2a (X-ray crystal structure analysis); Et: 2b; tBu: 2d; Ph: 2e], presumably via the unstable compounds bB(Et)OB(Et)OC(R)Ok(Et)OC(R)O (3a, b, d, e). Compound l c (R = CF3) reacts with A to form a mixture of 1,3-diethyl-1,3-bis(trifluoroacetoxy)diboroxane O=C(CF,)OB(Et)OB(Et)O(CF3)C=0 (2c') and 2c (R = CF,) at room temperature. Whereas two compounds of the type 2 do not comproportionate, l a -e spontaneously form the mixed substituted carboxylic acid anhydrides l a b etc. on mixing at room temperature (GC, I3C NMR). -From the I r 0enriched A* and l a -e the '?O-enriched compounds 2a*-e* with BO*B and > BO*OCR groups are obtained. A* exchanges 0 atoms up to 200°C with succinic anhydride (If) forming If* or with phthalic acid anhydride ( l g ) forming l g ' and 3g*. -The mixed carboxylic acid anhydrides lxy are cleaved, and the mixtures of 1 are separated with A to yield the uniform 3,7-dialkyl-substituted compounds 2.In unsere Untersuchungen zur Ubertragung von Sauerstoffatomen auf und von Organobor-Verbindungen[*I haben wir das praparativ vielseitig venvendbare Triethylboroxin einbezogen und berichten hier uber dessen Reaktionen rnit den Carbonsaureanhydriden (RCO)20 (la-e). Auf einem einfachen, ubersichtlichen Weg konnten dabei die zweifach ringstabilisierten 1,3-Bis(acyloxy)-1,3-diethyIdiboroxane 2a-e hergestellt und daruber hinaus die Komproportionierung der Anhydride 1 a-e zu den gemischt-substituierten Verbindungen lab-lae analytisch nachgewiesen werden.Zum Verfolgen der Reaktion nach G1. (a) haben wir 1 7 0angereichertes Triethylboroxin eingesetzt und dessen Verhalten auch gegenuber den cyclischen Anhydriden If und l g untersucht. Diethylborylpivalat (B)I41 und Tetraethyldiboroxan (C)I51 sind zusatzlich fur regioselektive I7O-Dotierungen verwendet worden. Herstellung von 2a-e aus A und la-eDie praparative Gewinnung der gemischten Anhydride 2a-e aus Triethylboroxin (A) und den Carbonsaureanhydriden la-e nach der G1. (a) liefert keine Nebenprodukte, im Gegensatz zu allen bisher durchgefuhrten ReaktionenI6].1,3-Bis(acyloxy)-l,3-diorganodiboroxane, die in Losung bevorzugt und im festen Zustand ausschliefilich als Chelatstabilisierte 4,8,9-Trioxa-2,6-dioxonia-l,5-diboratabicyclo-[3.3.1]nona-2,6-diene (2) v~rliegen[~.~I, sind meist unter Verwendung protonenhaltiger Verbindungen hergestellt worbeispielsweise aus Triorganoboranen, (Acy1oxy)dialkylboranen oder Tetraorganodiboroxanen mit freien Carbonsauren[8a] sowie aus Alkyldihydroxyboranen[8b] mit Carbonsaureanhydriden. Auch Halogen-organoborane wurden mit Carbonsauren in die Diboroxane des Typs 2 ubergefiihrt[8cl. Triethylboroxin (A), das sich u.a. zur Herstellung von Triethyl...

9-Fluoro-9-borabicyclo[3.3.l]nonane -Characterization in Solution and in the Solid State') 9-Fluoro-9-borabicyclo[3.3.l]nonane (l), prepared from bis(9borabicyclo[3.3.1]nonane) with SbF3 or SbF5 in high yields, is characterized by IR, mass, and multi-NMR spectroscopy. Pure 1 in solution has a small llB-NMR singlet signal in contrast to the freshly prepared 1 with the normal &,-split "B resonance.The X-ray structure analysis of 1 with three differently bonded molecules 1-111 (Abb. 2) in the cell shows a monomer and a dimer of 1 with BFB coordination bond. -Some Lewis base adducts of 1 are prepared, the others were characterized by "B-NMR spectra.

Crystalline Sodium Triethylhydroborate — Formation and Characterization Two equiv. of NaHBEt3 (1) and one equiv. of mesitylene form a crystalline compound, which is characterized by DSC and by a single‐crystal X‐ray structure analysis at 190 K as the solid phase 2.

Trialkylphosphitc P(0Rh [R = CHI (24, C a H , ~~ Verbindung Redusicrbar NEIN J A J A NEIN NEIN J A Verbindung Rcdusie rbar NEIN NEIN J A J A J A J A~ ) -13351861 "I K.

Both selenium dioxide (1) and selenium bis(tert-butylimide) (2) react with triethylborane (A) by 1,2-ethyloboration. In the case of 1, ethane, ethene, diethylselane (4a), tetraethyldiboroxane (Et,B),O (B), triethylboroxine (EtB0)3 (D) and a cyclic compound [ -Et,BOSe(Et)O-], (5,) are formed after heating to 65 "C. Compound 5, is also formed when 1 reacts with B. Treatment of selenous acid (3) with A or, preferentially for synthetic purposes, with B provides further routes to 5,. The reaction of the diimide 2 with A starts already below -50°C: a cyclic ethaneselenic acid derivative 6, E t 2 m Se(Et)fitBu, is formed, and 6 starts to decompose at -50°C by elimination of ethene to give finally (tert-buty1amino)die- More than 20 years ago it was shwon that selenium dioxide (1) reacts with triethylborane (A) in aqueous solution or in tetrahydrofuran (THF) to give diethylselane (4a) and diethyldiselane (4b)L'I. The formation and isolation of potential intermediates was not considered, and a radical mechanism was proposed for the BISe alkyl transferL2]. In continuing studies of the reactivity and synthetic application of A and organoboron-oxygen compounds such as (Et2B)O (B), (9-BBN)20 (C), and (EtBO), (D)L31, we have investigated their reactions with selenium dioxide (l), selenium bis(tert-butylimide) (2)r4], and selenous acid (3). In addition, transborylations using C were attempted in order to prepare reasonably stable intermediates, hoping to take advantage of the higher crystallization tendency of the 9-BBN derivativesL3fl. Compound 52 is also formed in the reaction of 1 with an excess of (Et,B),O (B). The I70-NMR spectrum shows signals for B(170), D(I7O>, and the broad signal at 6 = 130 corresponding to S2, by using B(170). In contrast, the reaction of (EtB0)3 (D) with 1 does not lead to S2 but to a redChem.