Boranes hydroxy compound

Most reported boric acid esters are trialkoxy or triaryloxy boranes. The esters range from colorless low boiling Hquids to soHds that possess high melting points. Boric acid esters usually have an odor similar to the hydroxy compound from which they are derived. A more complete description of the physical... 

BENZYL FORMATE (104-57-4) C,H,Oj Forms explosive mixture with air (flashpoint 107°F/42°C). Violent reaction with oxidizers. Incompatible with nitrates bases, amines, amides, inorganic hydroxides boranes, chlorosilanes epoxides hydroxy compounds. On small fires, use dry chemical powder (such as Puiple-K-Powder), foam, or COj extinguishers. 

The colorless, vacuum-distillable liquid [(2,2-dimethylpropanoyl)oxy]diethyl-borane (2,2-dimethylpropanoyl = pivaloyl) is a catalyst for the introduction of diethylboryl groups onto the oxygen atoms of hydroxy compounds using tri-ethylborane, Diethylborylations of hydroxy compounds have both preparative " and analytical (determination of the ethane value EZ ) uses. [(2,2-Dimethylpropanoyl)oxy]diethyIborane is itself a reagent for preparing aldol-condensation products" and for determining analytical pivalate values (PZ) of H-acidic compounds. ... 

DHV3-III. Cleavage of the intennediate boranes in these reactions by acetic acid was not very efficient making this a poor preparative method for these compounds. If the boranes were cleaved by alkaline hydrogen peroxide, however, high yields of the corresponding mixture of 19-hydroxy derivatives were obtained. One of these, (121), has shown interesting anti-vitamin D3 activity. 

Other chiral phosphine-phosphites with relevance to application in AHF are those derived from BIPHEN (Scheme 2.141), as claimed by ChiroTech Technology Ltd./Dr Reddy s Laboratories [35]. Their total synthesis starts with enantiopure l-hydroxy-2,5-diphenylphospholane 1-oxide, which is available via a multistep approach suggested by Fiaud et al. [36]. This material is converted via its borane adduct into the corresponding hydroxymethyl compound by addition to paraformaldehyde. Phosphorylation of the alcohol with enantiopure BIPHEN-X (X = C1, Br, or I) produces the phosphite. The use of phosphorbromidite or the relevant iodide sometimes avoids the need for higher temperatures, which... 

Optically active (3-hydroxy sulfides 48 and sulfones 50 are extremely useful chiral building blocks because the a-carbon atom can be further functionalized and the sulfinyl and sulfonyl groups can be cleaved easily without racemization of the chiral center. Recently, Cho and co-workers reported highly effective syntheses for these compounds with excellent enantioselectivities by the 2b-catalyzed borane reduction of (3-keto sulfides 47 and sulfones 49 using EIANB (9) as the borane reagent (Table 11.9). The reduction is very effective for both aromatic and hindered aliphatic analogues [74, 75]. 

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