DIBORANES DERIVED FROM HYDROBORATION OF 1,3-BUTADIENE . STRUCTURES HYDROGEN-BRIDGE CLEAVAGE REACTIONS AND FACTORS WHICH AFFECT COURSE OF BRIDGE CLEAVAGE

Convenient syntheses of 1,2-tetramethylenediborane(6) (I) and l,2-bis(tetramethylene)diborane(6) (II) have been developed. It has been possible to distinguish between II and l,1-tetramethylene-2,2-tetramethylene-diborane(6) (III) and show that II is the product prepared in the synthetic procedures employed. Ammonia and methylamines react with I and II to produce either symmetrical or unsymmetrical cleavage of the hydrogen-bridge system, with the unsymmetrical cleavage products being zwitterions. The type of cleavage product formed (identified by boron-11 nmr) depends upon the reactants. Factors which affect the course of cleavage are considered and discussed. © 1969, American Chemical Society. All rights reserved.