1,1 -Diboryl compounds

Diboryl compounds yield alkenes on reaction with chromic acid (equation 45), a reaction also noted in a peracid oxidation and oxidation with pyridinium chlorochromate. ... 

Diboryl compounds do not yield aldehydes with alkaline hydrogen peroxide. Instead there is r d hydrolysis, presumably via a boron-stabilized carbanion (see Volume 1, Ch ter 2.6) which is protonated and then oxidized to the alcohol (equation 16). ... 

The key step to the tricyclic compound 17 seems to be the stereoselective aza Diels-Alder reaction (20) of the intermediate enamine dienophile 18 with azadiene adduct 19 to produce the imine complex 21. Allylboration of C=N bond in the latter proceeds also stereoselectively (21, arrow) furnishing the diborylated compound 22. 

Hydroboration of internal alkynes with 9-BBN-H in stoichiometric amounts is a useful way of synthesizing vinylboranes (Scheme Further hydroboration of the product is slow, but can be used to produce g /n-diboryl compounds (Scheme 6). ... 

Diboryl compounds (6) are made by reaction of certain dialkylboranes, generally dicyclohexyl-borane [(C- 6Hn)2BH], disiamylborane (Sia2BH) or 9-borabicyclo[3.3.1]nonane (9-BBN-H), with 1-alkynes (equation i).Wti6-is... 

Although cleavage of gem-diboryl compounds is a mild and general process for die production of boron-stabilized carbanions, it nevertheless suffers from two disadvantages. Firstly, although... 

Diboron tetrafluoride and diboron tetrachloride add to the unsaturated bond of methylenecyclopropane and vinylcyclopropane to yield the new diboryl compounds (1) and (2), respectively. ... 

The chemistry and stereochemistry of aminoboranes containing the siLicon—nitrogen—boron linkage have been the subject of numerous studies. Many of these compounds are useful precursors to other B—N systems including diboryl-amines (45) and B—H substituted aminoboranes (46). A series of... 

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