Ketone halogenation

Aldehyde or ketone Halogen a Halo aldehyde or ketone Hydrogen halide... 

In spite of these rationali2ations, the stereochemistry of ketone halogenation retains some puzzling features. For example, the effect of a 2-methyl substituent on the direction of bromination at C-2 is unexpected. 

Remarkably, ketone halogenation also occurs in biological systems, particularly in marine alga, where dibromoacetaldehyde, bromoacetone, 1,1,1-tri-bromoacetone, and other related compounds have been found. 

Problem 22.9 Why do you suppose ketone halogenations in acidic media referred to as being ackl-calalyzed, whereas halogenations in basic media are base-promoted In other words, why is a full equivalent of base required for halogenation ... 

Halogenation of Aldehydes and Ketones Halogenation or Halo-de-hydrogenation... 

The ROMP of alcohol, ketone, halogen, and acetate substituted cyclooctenes with a ruthenium olefin metathesis catalyst has been reported (31). 

Very little work has been done on selectivity in anodic reactions of pyridines. Selective methoxylation and acetoxylation are known for al-kylbenzenes, but such reactions have not been reported for alkylpyridines. Also, reports on the oxidation of pyridines having aldehyde, ketone, halogen, hydroxyalkyl, or aminoalkyl functionalities are sparse. 

For halogenated compounds For aldehydes, ketones, halogenated compounds, hydrocarbons, phosphorus compounds... 

A group of substances which are closely associated with the gas hydrates, are the compounds of urea (and thiourea) with a large number of organic substances with long-chain molecules, such as normal saturated hydrocarbons and olefins, alcohols, acids, esters, ketones, halogenated hydrocarbons, etc.3, which were discovered accidentally by Bengen in 1940. These compounds are only produced with unbranched, non-cyclic molecules4. This is even so very specific that a method of separation can be based on it for normal and iso hydrocarbons in mixtures. 

Halogenation Alkyl Ketones Halogenation ot the a or a position of carbonyl 320,1036.1037... 

Problem 22.9 Why do you suppose ketone halogenations in acidic media referred to as being acid-... 

The first substitution reaction we examine is halogenation. Treatment of a ketone or aldehyde with halogen and either acid or base results in substitution of X for H on the a carbon, forming an a-halo aldehyde or ketone. Halogenation readily occurs with CI2, Br2, and I2. 

---