Process for the preparation of thietane derivatives

1. A process for preparing a compound of formula X

comprising

i. reacting a compound of formula VII

with triphenylphosphoranyldiene-acetonitrile or (Cyanomethyl)diethoxyphosphine oxide to give a compound of formula VIII

ii. reducing the compound of formula VIII with a suitable reducing agent to give a compound of formula X.

2. A compound of formula IB or IA

wherein

A 1 , A 2 , A 3 and A 4 are independently of one another C—H, C—R 3 , or nitrogen;

B is O,

R 1 is C 1 -C 8 haloalkyl;

R 2 is aryl or aryl substituted by one to five R 4 , or heteroaryl or heteroaryl substituted by one to five R 4 ;

each R 3 is independently halogen, cyano, nitro, C 1 -C 8 alkyl, C 3 -C 8 cycloalkyl, C 1 -C 8 haloalkyl, C 2 -C 8 alkenyl, C 2 -C 8 haloalkenyl, C 2 -C 8 alkynyl, C 2 -C 8 haloalkynyl, C 1 -C 8 alkoxy, C 1 -C 8 haloalkoxy, C 1 -C 8 alkoxycarbonyl-, amino, hydroxy, mercapto, C 1 -C 8 alkylthio, C 1 -C 8 haloalkylthio, C 1 -C 8 alkylsulfinyl, C 1 -C 8 haloalkylsulfinyl, C 1 -C 8 alkylsulfonyl, C 1 -C 8 haloalkylsulfonyl, C 1 -C 8 alkylcarbonyl, or two R 3 on adjacent carbon atoms together form a —CH═CH—CH═CH— bridge or a —N═CH—CH═CH— bridge;

each R 4 is independently halogen, cyano, nitro, C 1 -C 8 alkyl, C 1 -C 8 haloalkyl, C 2 -C 8 alkenyl, C 2 -C 8 haloalkenyl, C 2 -C 8 alkynyl, C 2 -C 8 haloalkynyl, hydroxy, C 1 -C 8 alkoxy, C 1 -C 8 haloalkoxy, mercapto, C 1 -C 8 alkylthio, C 1 -C 8 haloalkylthio, C 1 -C 8 alkylsulfinyl, C 1 -C 8 haloalkylsulfinyl, C 1 -C 8 alkylsulfonyl, C 1 -C 8 haloalkylsulfonyl, C 1 -C 8 alkylcarbonyl, C 1 -C 8 alkoxycarbonyl, aryl or aryl substituted by one to five R 5 , or heterocyclyl or heterocyclyl substituted by one to five R 5 ;

each R 5 is independently halogen, cyano, nitro, C 1 -C 4 alkyl, C 1 -C 4 haloalkyl, C 1 -C 4 alkoxy-, or C 1 -C 4 haloalkoxy-;

n is 0, 1 or 2.

3. A compound of formula XV

wherein n is 1 or a compound of formula XI, XII or XIII

wherein R is C 3 -C 6 alkyl.

4. A method of combating and controlling insects, acarines, nematodes or molluscs which comprises applying to a pest, to a locus of a pest, or to a plant susceptible to attack by a pest an insecticidally, acaricidally, nematicidally or molluscicidally effective amount of a compound of formula (IB) as defined in claim 2 .

5. An insecticidal, acaricidal, nematicidal or molluscicidal composition comprising an insecticidally, acaricidally, nematicidally or molluscicidally effective amount of a compound of formula (IB) as defined in claim 2 , and optionally comprising an additional pesticidally active ingredient.

6. A combination product comprising a pesticidally effective amount of a component A and a pesticidally effective amount of component B, wherein component A is a compound of formula (IB) as defined in claim 2 , and component B is imidacloprid, enrofloxacin, praziquantel, pyrantel embonate, febantel, penethamate, moloxicam, cefalexin, kanamycin, pimobendan, clenbuterol, fipronil, ivermectin, omeprazole, tiamulin, benazepril, milbemycin, cyromazine, thiamethoxam, pyriprole, deltamethrin, cefquinome, florfenicol, buserelin, cefovecin, tulathromycin, ceftiour, selamectin, carprofen, metaflumizone, moxidectin, methoprene (including S-methoprene), clorsulon, pyrantel, amitraz, triclabendazole, avermectin, abamectin, emamectin, eprinomectin, doramectin, selamectin, nemadectin, albendazole, cambendazole, fenbendazole, flubendazole, mebendazole, oxfendazole, oxibendazole, parbendazole, tetrami sole, levami sole, pyrantel pamoate, oxantel, morantel, triclabendazole, epsiprantel, fipronil, lufenuron, ecdysone or tebufenozide.

7. The compound of claim 3 , wherein the compound is the compound of formula XV.

8. The compound of claim 3 , wherein the compound is the compound of formula XI.

9. The compound of claim 3 , wherein the compound is the compound of formula XII.

10. The compound of claim 3 , wherein the compound is the compound of formula XIII.

11. The compound of claim 8 , wherein R is C 3 alkyl.

12. The compound of claim 8 , wherein R is C 4 alkyl.

13. The compound of claim 8 , wherein R is C 5 alkyl.

14. The compound of claim 8 , wherein R is C 6 alkyl.