Vinyl chloroformates are described of formula ##STR1## in which: R.sub.1 .dbd.R.sub.2 .dbd.Cl, Br or a saturated 1-4 carbon atom alkyl or together they form a cycloaliphatic ring of 4-8 carbon atoms; R.sub.3 .dbd.H when R.sup.1 or R.sup.2 .dbd.alkyl; saturated alkyl of 1-4 carbon atoms or aryl; ##STR2## in which R.sub.4 .dbd.R.sub.5 .dbd.alkyl of 1-4 carbon atoms or R.sub.3 forms with R.sub.2 a C.sub.5 -C.sub.8 ring which may have attached oxygen atoms. The process of preparation consists of reacting phosgene with the corresponding compounds containing alpha halogen and a carbonyl group. The products are very useful to obtain vinyl carbonates and carbamates.
α-Phenylselanyl aldehydes are prepared on a large scale by reaction of PhSeCl3 with the corresponding aldehydes in acetonitrile without isolation of the intermediate dichloro adducts. This method has been applied to α-phenylselanyl ketones derived from alkyl aryl ketones, symmetrical aliphatic ketones and alkyl isopropyl ketones. cis-4-tert-Butyl-2-phenylselanylcyclohexanone was also prepared in the same way.