![]() The recommended way of performing these reductions is to add an equimolar mixture of aluminum chloride and the ketone in ether to an equimolar mixture of aluminum chloride and LiAlH4 in ether. Diaryl ketones, alkylaryl ketones and some aryl alcohols are smoothly reduced to the corresponding hydrocarbons. The course of reduction of unsaturated and aromatic ketones is more complicated. Diaryl ketones, generally unreactive compounds, react rapidly when R = Cl. When R = Ph, the reaction is selective for unhindered ketones. The intermediate in the cycloaddition was found to be (386), which on heating lost CO to form a new ylide system which in turn underwent reaction with more DMAD <81JA7743). Double bond migration in (384) occurred on heating to give (385). Reaction of (383) with DMAD in methylene chloride gave (384), a 2 1 adduct with loss of CO. Treatment of a-chloroacylhydrazones of diaryl ketones and certain aralkyl and dialkyl ketones (382) with NaH in anhydrous THF gives l-(disubstituted methylene)-3-oxo-l,2-diazetidinium inner salts (383). In the alternative approach.the 1,3-dipolar system can be constructed in several ways. Acetophenone (531) is obtained by the carbonylation of iodobenzene with Me4Sn. Ketones diaryl Organotin compounds such as aryl-, alkenyl-, and alkynylstannanes are useful for the ketone synthesis by transmetallation of acylpalladium 529 and reductive elimination of 530 as shown. ![]()
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