1,1-Dibora compounds

Proceeding to two rings going-on one class, neutral derivatives of bicyclobutane with the two non-bridgehead carbons replaced by sp hybridized or trigonally coordinated atoms show self-destructive behavior for related reasons (see Chapter 19 by Hoz for a review of bicyclobutanes). Our suicidal species include the hypothetical bicyclobutane-2,4-dione (51) and its 1,3-disubstituted derivatives, recognized as squaraines (52) . The theoretical analysis of the parent diketo compound suggests the non-planar form also lacks the C-C bond. The 2,4-dibora compounds are experimentally known to be... 

Steric hindrance in aryl-substituted borazines depends on o-substitu-tion of the aryl groups. Significant results concerning the reaction of primary arylamines with trihaloboranes, have recently been discussed in detail 89>9°). While pyrolysis of aniline-trihaloboranes or o-toluidine-trihaloboranes yields the corresponding B-trichloroborazines, the base-promoted dehydrohalogenation of the latter results in the formation of a l,3-diazaro-2,4-dibora-naphthalene compound besides a minor amount of borazine. 

Hydroboration of allenes. With few exceptions, the 9-BBN hydroboration of allenes affords B-allylic-9-BBN derivatives. In contrast, the reactions of allenes with disiamylborane or dicyclohexylborane afiord predominantly vinylic boranes. With unsymmetrical allenes, 9-BBN binds to the less substituted carbon atom. Allene itself affords a 1,3-dibora derivative. The B-allylic-9-BBN derivatives are useful reagents for the allylic boration of carbonyl compounds. ... 

The compound prepared in this way is the symmetric isomer obtainable also by the active metal coupling reaction or by the reaction of butyllithium with the product obtained from treatment of B2[N(CH3)2]2(C4H,)2 with HCl (79). Formation of a compound formulated as 9,10-dibora-9,10-bis(dimethylamino)phenanthrene has been reported from the reaction of l,2-bis(dimethylamino)-l,2-dichlorodiborane(4) with magnesium and 2,2 -dibromobiphenyl (5J). 

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