Process for the preparation of 1,1-dichloro-alkenes

• Main Authors: MAURER; FRITZ, PRIESNITZ; UWE, RIEBEL; HANS-JO
• Format: Patent
• Language: English
• Published: 21.09.1982
• Subjects: ACYCLIC OR CARBOCYCLIC COMPOUNDS; CHEMISTRY; METALLURGY; ORGANIC CHEMISTRY

A process for the preparation of a 1,1-dichloroalkene of the formula in which R1 is hydrogen, or an optionally substituted alkyl, alkenyl, alkinyl, cycloalkyl, aralkyl, aralkenyl or aryl radical, and R2 is an optionally substituted alkyl, alkenyl, alkinyl, cycloalkyl, aralkyl, aralkenyl or aryl radical, or R1 and R2 together form an optionally branched and/or optionally benzo-fused hydrocarbon chain, comprising reacting a carbonyl compound of the formula with a trichloromethanephosphonic acid ester of the formula in which R3 each individually is an alkyl or phenyl radical, or the two radicals R3 together are alkanediyl, in the presence of at least an equimolar amount of a phosphorous acid triamide of the formula P(NR42)3 in which R4 each independently is an alkyl radical, or the two radicals R4 together are alkanediyl. Advantageously, R1 is hydrogen, R2 a C2 to C5 alkenyl radical, or a radical of the formula Z is a cyano, acetyl, carboxyl or C1 to C4 alkoxycarbonyl radical, or a radical of the formula -COOM, M is sodium or potassium, and R3 each individually is a C1 to C4 alkyl or phenyl radical, or the two radicals R3 together are C2 to C5 alkandiyl, the phosphorous acid triamide is phosphorous acid tris-dimethylamide or tris-diethylamide, about 0.94 to 1.1 moles of each of trichloromethanephosphonic acid ester and of the phosphorous acid triamide are employed per mole of the carbonyl compound, and the reaction is effected at about 10 DEG to 100 DEG C. in a polar aprotic solvent.