- Beitraege zur Chemie des bors, 226: Funktionalisierung von Alkinylboranen-Umsetzung mit Nucleophilen
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The synthesis of alkynylboranes RR'B-CC-R" 1-3 and their reactions with various nucleophiles are described (R, R' = Me2N, Cl, alkyl; R" = Me, Ph).Although these compounds can be looked upon as inorganic Michael systems, nucleophiles such as alcohols, amines, amides and various carbon nucleophiles attack exclusively at the boron atom (analogous to a 1,2- attack).Thus, a nonvenient means of functionalization of alkynylboranes at the boron atom with preservation of the B-CC moiety is described, and alkynylboranes with R,R' = Me2N, N(H)iPr, pyr, OiPr, Me, Mes, CC-SiMe3 were obtained in good yield and characterized by spectroscopic methods.The pathway for the reaction of (Me2N)2B-CC-Ph with carbon nucleophiles to tris(alkyl)boranes has been elucidated.The implications both for the electronic properties and the chemical reactivity of alkynylboranes are discussed.Keywords: Alkynylboranes, Nucleophilic attack, Organoboron compounds, Inorganic Michael systems; Boron; Alkyne
- Feulner, Herta,Metzler, Nils,Noeth, Heinrich
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- Rearragement and Degradation of Bicyclic Amine-Tetraalkyldiboroxanes
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The amine-tetraalkyldiboroxanes 1,4,7,7' = Et; 1b: R1,4,7 = Et, R7' = Ph; 1b': R4,7,7' = Et, R1 = Ph; 1c: R1,7,7' = Et, R4 = Ph> react on heating by EtBO elimination and allylborane rearrangement to yield the allyl-aminoboranes Me2NB(Et)CH2C(R4)=C(R7,7') 4,7,7' = Et, 2b/2b': R4 = Et, R7,7' = Et, Ph; 2c: R4 = Ph, R7,7' = Et>: On heating above 60 deg C the diastereomeric syn/anti-1d/1d' (1d: R1,7 =C8H14, R4,7' = Et; 1d': R1,7' = C8H14, R4,7 = Et) give the unsaturated rac-amino-trialkyldiboroxane (rac-3) (X-ray structure analysis) by intramolecular 1,2-deaminoboration. rac-3 is characterized by reaction with (Et2BH)2 and (Et2BD)2 with formation of the 1,2,6-oxadiborinane 5 by evolution of H2 or HD respectively.The intramolecular CH-borylation of rac-3 is compared with those of the thujopsen hydrocarbons I-III. - Key Words: Amine-Diboroxanes, bicyclic / 1,2-Deaminoboration, intramolecular / Deoxy boration / Allyl-aminoboranes, organosubstituted, rearrangement / C-Borylation
- Koester, Roland,Schuessler, Wilhelm,Seidel, Guenter,Blaeser, Dieter,Boese, Roland
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p. 1843 - 1850
(2007/10/02)
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