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Addition of Ketones to Nitroolefins and Alkylidene Malonates

Addition of Ketones to Nitroolefins and Alkylidene Malonates 2.3.3.1 Proline [Pg.79]

Modification of the proline structure leads to more efficient chiral pyrrolidine catalysts, showing better selectivity and improved synthetic scope. [Pg.79]

2 Pyrrolidine Amines and Pyrrolidine Amine Salts as Catalysts for Michael-Type Addition of Ketones to Activated Olefins [Pg.79]

Whilst in some cases near-stoichiometric amounts of reagents can be used [16], the excess (5-10 equiv.) of ketone reagent is preconceived in order to ensure convenient kinetics and conversion. Reactions can be run typically at room temperature [20] in a polar aprotic solvent such as CHC13, or in THF or i-PrOH. The presence of water was noted to be beneficial in some cases [21]. In ionic liquids, such as in [bmim]BF4, a low (5 mol%) catalyst concentration can be applied, while the enantioselectivity of the alkylation is modest in this solvent [22]. The ionic liquid-derived hybrid catalyst 10, used neat with a small amount of trifluoroacetic acid (TFA) as co-catalyst, affords quantitatively 4, though in a remarkably high dr syn/anti = 99/1) and ee (99%). It should be noted that this catalyst can easily be recovered by extraction, and re-used without loss of activity. [Pg.81]




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Addition ketones

Addition to ketones

Alkylidene malonate

Alkylidene malonates

Ketones alkylidenation

Malonates additions

Nitroolefin

Nitroolefination

Nitroolefins

Of nitroolefines

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