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Asymmetric allenylboration

Insertion Reactions. Trimethylsilyldiazomethane undergoes net insertion between the B-C bond of borinate and boronate esters. Thus, olefin hydroboration, followed by treatment with TMSCHN2, oxidation, and desilylation offers a method for hydroxymethylation of alkenes in fair to moderate yield (eq 54). Stable, chiral allenylboranes (IR and IS) are prepared by reaction of TMSCHN2 with 5-MeO-9-BBN followed by resolution with pseudoephedrine and reaction with allenyl magnesium bromide (eq 55). Compounds IR and IS are useful for the asymmetric allenylboration of aldehydes with predictable absolute stereochemistry. The precursors to 1 are then readily recovered during work-up. ... [Pg.548]

See other pages where Asymmetric allenylboration is mentioned: [Pg.631]    [Pg.472]    [Pg.473]    [Pg.480]    [Pg.480]    [Pg.480]    [Pg.481]    [Pg.472]    [Pg.473]    [Pg.480]    [Pg.480]    [Pg.480]    [Pg.481]    [Pg.177]    [Pg.177]    [Pg.189]    [Pg.190]    [Pg.455]   
See also in sourсe #XX -- [ Pg.472 ]

See also in sourсe #XX -- [ Pg.472 ]



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