Hooz reaction trialkylborane

A study on stereodefined boryl enolates that employed both pure (Z)- and ( )-dialkylboryl enolates has been carried out by Masamune et al Hooz reaction involving a-diazocarbonyi compounds (Scheme 3) and a trialkylborane provides exclusively (0)-alkenyloxyboranes, which can be isomerized cleanly to the corresponding Z(0)-isomers.- The Z((9)-dibutylboryl enolates (17) react with various aldehydes exhibiting uniformly high syn selectivities (syn.anti > 95 5), while the corresponding (0)-isomers (18) are converted into the anti aldol products with somewhat lower selectivities (Scheme 15). 

Kegiospecific synthesis of Manmch bases. Hooz and Bridson have described a new rcgiospecific synthesis of certain Mannich bases which involves first reaction of a trialkylborane with an a-diazoketone in THF to form an cnol borinate (1) after evolution of nitrogen ceases, dimcthyl(methylene)ammonium iodide (2) in DMSO is added. The Mannich base (3) is obtained in 85 100% yield after hydrolytic workup. Cosolvent DMSO is crucial for high yields. 

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See also in sourсe #XX -- [ ]

See also in sourсe #XX -- [ ]

See also in sourсe #XX -- [ ]

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