1-Haloalkenes

Sulfur tetrafluoride [7783-60-0] SF, replaces halogen in haloalkanes, haloalkenes, and aryl chlorides, but is only effective (even at elevated temperatures) in the presence of a Lewis acid catalyst. The reagent is most often used in the replacement of carbonyl oxygen with fluorine (15,16). Aldehydes and ketones react readily, particularly if no alpha-hydrogen atoms are present (eg, benzal fluoride [455-31-2] from benzaldehyde), but acids, esters, acid chlorides, and anhydrides are very sluggish. However, these reactions can be catalyzed by Lewis acids (HP, BF, etc). 

The most frequentiy used halo alkylating agents are aldehydes and hydrogen haUdes, haloalkyl ethers, haloalkyl sulfides, acetals and hydrogen haUdes, di- and polyhaloalkanes, haloalkenes, haloalcohols, haloalkyl sulfates, haloalkyl -tosylates, and miscellaneous further haloalkyl esters. Haloalkylations include halomethylation, haloethylation, and miscellaneous higher haloalkylations. Under specific conditions, bis- and polyhaloalkylation can also be achieved. 

When X=OH, this conversion of acetylenic alcohols to unsaturated aldehydes or ketones is called the Meyer-Schuster rearrangement The propargyl rearrangement can also go the other way that is, 1-haloalkenes, treated with organocopper compounds, give alkynes. ... 

The F / Cl exchange in chloroalkanes is a route to HFCs. For example, different routes can be possible for the synthesis of CF3CH2F [1,2 ]. Our focus is on its preparation from CF3CH2CI and HF with chromium (HI) oxide as a catalyst. This fluorination is accompanied by a dehydrofluorination which produces chloroalkenes (mainly CF2=CHC1) resulting in a deactivation of the catalyst Indeed this haloalkene could polymerise and thus lead to coke formation. The reactions involved are ... 

The decarboxylation of carboxylic acid in the presence of a nucleophile is a classical reaction known as the Hunsdiecker reaction. Such reactions can be carried out sometimes in aqueous conditions. Man-ganese(II) acetate catalyzed the reaction of a, 3-unsaturated aromatic carboxylic acids with NBS (1 and 2 equiv) in MeCN/water to afford haloalkenes and a-(dibromomethyl)benzenemethanols, respectively (Eq. 9.15).32 Decarboxylation of free carboxylic acids catalyzed by Pd/C under hydrothermal water (250° C/4 MPa) gave the corresponding hydrocarbons (Eq. 9.16).33 Under the hydrothermal conditions of deuterium oxide, decarbonylative deuteration was observed to give fully deuterated hydrocarbons from carboxylic acids or aldehydes. 

Electrophilic addition to 1-haloalkenes (e.g. 27), presents a number of parallels to the electrophilic substitution of halobenzenes (p. 155). Thus it is the involvement of the electron pairs on Br that controls the orientation of addition (cf. o-/p-direction in C6H5Br) ... 

See Dichloroacetylene also Trichloroethylene Alkali See other HALOALKENES... 

See other HALOALKENES, peroxidisable compounds 0731. 1 -Chloro-1,1-difluoroethane... 

Colombo, P. et al., J. Polymer Sci., 1963, Bl(8), 435-436 Mixtures containing ratios of about 20 1 and 12 1 of ethylene haloalkene undergoing polymerisation under gamma irradiation at 308 krad/h exploded violently after a total dose of 50 krad. Dose rate and haloalkene cone, were both involved in the initiation process. 

See Benzyltrimethylammonium hydroxide, etc., and Bases, both above See other cyano compounds See related haloalkenes... 

Bromo-l-propene (Allyl bromide) [106-95-6] H2C=CHCH2Br HCS 1980, 124 See other allyl compounds, haloalkenes C3H5Br... 

Chloro-l-propene [590-21-6] ClCH=CHMe See other HALOALKENES C3H5C1... 

See other ALLYL COMPOUNDS, HALOALKENES, iodine compounds... 

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