ISSN:
0009-2940
Keywords:
1,2,5-Oxoniadiboratoles, 2,5-dihydro-, organo-substituted
;
1,2,5-Oxadiborolanes, organo-substituted
;
1,3,2-Diboroxanes, substituted with unsaturated residues
;
Boryl-germyl exchange
;
cis-1,2-Diborylalkenes, organo-substituted
;
Chemistry
;
Inorganic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Substituted 2,5-Dihydro-1,2,5-oxoniadiboratoles, cis-1,2-Diborylalkenes, and 1,2,5-Oxadiborolanes - Preparation and CharacterizationThe potassium salts (A: R = R′ = Et; B: R2 = C8H14, R′ = Me; C: R2 = C8H14, R′ = Et) react with various electrophiles (H+, R+, Me3ElIV+) to form substituted 1,3,2-diboroxanes (1, iso8b) including 1,2,5-oxadiborolanes (2, 4, 6, 9, 10), dialkylvinylboranes (1'), 2,5-dihydro-1,2,5-oxoniadiboratoles (3, 5) and cis-1,2-diborylalkenes (7, 8). In particular, A-C react with HCl (as Me3NHCl/THF or HCl/Et2O) to give O[B(Et)C(Et) = CHR]2 (1a: R = Me; 1b: R = Et), R2BCR′ = CHEt (1'a: R = R′ = Et; 1'b: R2 = C8H14, R′ = Me; 1'c: R2 = C8H14, R′ = Et) and (2a: R,R′ = Et; 2b: R2 = C8H14, R′ = Me; 2c: R2 = C8H14, R′ = Et). With MeI in THF the cyclic compounds (3a) or (4b/4'b: R = Me; 4c/4'c: R = Et) and with Et3O · BF4 in CH2Cl2 the heterocycle - (5a) and cis-EtOB(C8H14)C(Et) = C(Et)BEt (5c) and/or (6b: R = Me; 6c: R = Et) are obtained. The reactions of A with ClElIVMe3 (ElIV = Si, Ge, Sn) lead to cis-Et2BC(Et) = CB(Et)OE1IVMe3 [ElIV=Si(7a), Ge (8a)] and to cyclic (9a). The salts B and C react with ClElIVMe3 (ElIV = Si, Ge) to form cis-C8H14BC(R) = C(Et)B(Et)OElIVMe3 (ElIV = Si: 7b: R = Me; 7c: R = Et; ElIV = Ge: 8b: R = Me, 8c: R = Et). On heating 8b isomerizes to cis-Me3GeC(Me) = C(Et)B(Et)OBC8H14 (iso8b). From B and C with ClSnMe3 the substituted 1,2,5-oxadiborolanes (10b/10'b: R = Me; 10c: R = Et) are obtained together with (C8H14B)2O.
Additional Material:
4 Tab.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/cber.19921250608
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