Homologation Ketone

Optically active a-chloro sulfoxides have recently been obtained by a very practical procedure using NBS and potassium carbonate with the expected inversion of configuration at sulfur. Chloro sulfoxides were shown to be very useful in the synthesis of epoxides and for a,3-unsaturated ketone homologation (Scheme 61b). ... 

Ketone homologation. The adducts of ketones with methoxymethy 1 phenyl sulfone... 

FIGURE 15. Effective phase ratio as a function of molar fraction of LPFOS in LDS for alkyl benzene and alkyl phenyl ketone homologous series. Data compiled from Reference 46. 

Aldehydes can be converted into ketones, ketones homologated, and cyclic ketones ring expanded via the insertion of an RCH unit [derived from the dibromoalkyl-lithium (43)] into the substrate the reaction may lead to mixtures of products depending on the nature of R and R (Scheme 36). ... 

In an unusual ketone homologation, attempted Wittig reaction of methyltriphenyl-phosphonium bromide with 2- (or 4-) methoxy-4 -nitrobenzophenone (134) using potassium f-butoxide as base unexpectedly yielded methyleneketones with the exclusion of triphenylphosphine. ... 

Annulation. 3-Trimethylsilyl-3-buten-2-one has been employed as a methyl vinyl ketone homolog in an improved method for the annulation of ketones. Based on work by Stork and Ganem, who employed 3-triethylsilyl-3-buten-2-one as a Michael acceptor in the Robinson annulation reaction, Suzuki and co-workers prepared a functionalized bicyclic ketone via a silyl enol ether as shown in eq 1. In general, the annulation of 2-alkylcycloketones with methyl vinyl ketone and its homologs produces rather poor yields of the desired cyclized products. 

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