New Preparations of Organoboron Compounds

9-Borabicyclo[3,3,l]nonane (9-BBN) has advantages as a hydroborating agent in several cases, because it is both sterically demanding and more sensitive than disiamylborane to electronic effects, and its B-alkyl derivatives are less susceptible than most organoboranes to thermal isomerization. Thus, for example, it can 

Trialkylboranes add across the triple bond of bis(trimethylstannyl)ethyne, to give organoboron species which look promising as synthetic reagents (reaction 

Hydroborations (BH3,THF) of compound types represented by (69), (70), and (71) presumably provide new approaches to organoboranes. However, these organoboranes were not isolated, but instead were worked up in situ with H2O2-OH, CrOa, or simple alkali to give (72), (73), and (74) respectively. 

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