Bulky derivatives of boranes, boronic acids and boronate estersvia reaction with diazomethanes

Abstract

Reactions of the perfluoroarylboranes RB(C(6)F(5))(2) (R = C(6)F(5), Ph, Cl, OC(6)F(5)) with Me(3)SiCH(N(2)), (C(6)F(5))CH(N(2)) or Ph(2)C(N(2)) yield (C(6)F(5))(2)B(Me(3)SiCH(C(6)F(5))) 1, (C(6)F(5))B(Me(3)SiCH(C(6)F(5)))(2) 2, (C(6)F(5))B(Me(3)SiCH(C(6)F(5)))(Me(3)SiCH(C(6)H(5))) 3, (C(6)F(5))(2)B(CH(C(6)F(5))(2)) 4, ClB(C(6)F(5))(Ph(2)C(C(6)F(5))) 5 and (C(6)F(5)O)B(C(6)F(5))(Me(3)SiCH(C(6)F(5))) 6 as a result of single or double insertion of a Me(3)SiCH, C(6)F(5)CH or Ph(2)C fragment into a B-C bond of the respective borane. Reactions of one or two equivalents of ethyl α-diazomethylacetate with B(C(6)F(5))(3) yielded (Me)(C(6)F(5))(C=C)(OC(2)H(5))(OB(C(6)F(5))(2)) 8 and [(Me)(C(6)F(5))(C=C)(OC(2)H(5))](2)(O(2)B(C(6)F(5))) 9, in addition to the corresponding pyridine adducts (Me)(C(6)F(5))(C=C)(OC(2)H(5))(OB(C(6)F(5))(2))(py) 10 and [(Me)(C(6)F(5))(C=C)(OC(2)H(5))](2)(O(2)B(C(6)F(5)))(py) 11. Similarly, reaction of α-diazomethylacetate with BPh(3) yielded analogous products of borane reorganization, (Me)(C(6)H(5))(C=C)(OC(2)H(5))(OBPh(2)) 12 and was isolated as a mixture of E and Z-isomers whereas BPh(3) reacts with Me(3)SiCH(N(2)) and pyridine yielding (py)B(Ph(2)(Me(3)SiCH(Ph)) 7. Reactions of Ph(2)C(N(2)) with RB(OH)(2) (R = C(6)F(5), p-F-C(6)H(4), C(6)H(5)) yielded cyclic boroxines of the form [Ph(2)C(R)BO](3) (R = C(6)F(5) 13, p-FC(6)H(4) 14, C(6)H(5) 15) while reactions of the boronate esters (C(6)H(4)O(2))BR (R = C(6)F(5), p-F-C(6)H(4)) with three or five equivalents of Me(3)SiCH(N(2)) yielded (C(6)H(4)O(2))B(Me(3)SiCH(Ar)) (Ar = C(6)F(5) 16, p-F-C(6)H(4) 17) and [(Py)B(C(6)H(4)O(2))(Me(3)SiCH(Ar))] (Ar = C(6)F(5) 18, p-F-C(6)H(4), 19) upon complexation with pyridine. Reaction of HBCat and ClBCat with Ph(2)C(N(2)) yielded the products of B-H and B-Cl bond derivatization (C(6)H(4)O(2))B(Ph(2)CR) (R = H 20, Cl 21), while the triethylphosphine oxide adduct (Et(3)PO)B(C(6)H(4)O(2))(CPh(2)Cl) 22, is readily isolable.