Microbiocidal oxadiazole derivatives

A compound of formula (I):

• wherein
• A1 represents N or CR1, wherein R1 is hydrogen, halogen, methyl, ethyl, difluoromethyl, trifluoromethyl, methoxy, ethoxy or difluoromethoxy;
• A2 represents N or CR2, wherein R2 is hydrogen, halogen, methyl, ethyl, difluoromethyl, trifluoromethyl, methoxy, ethoxy or difluoromethoxy;
• A3 represents Nor CR3, wherein R3 is hydrogen or fluoro;
• A4 represents N or CR4, wherein R4 is hydrogen or fluoro;
• and
• wherein no more than two of A1 to A4 are N;
• L1 represents —C(OH)(R6)—;
• R5 represents cyano, C1-6haloalkyl, cyanoC1-6alkyl, C1-3alkoxyC1-4alkyl, C1-2fluoroalkoxyC1-4alkyl, C3-6alkenyl, C3-6alkynyl, C3-8cycloalkyl or C3-8cycloalkylC1-2alkyl wherein the cycloalkyl moiety is optionally partially unsaturated, phenyl, phenylC1-2alkyl, heteroaryl bonded to L1 through a carbon atom or heteroarylC1-2alkyl, wherein the heteroaryl moiety is a 5- or 6-membered monocyclic aromatic ring which comprises 1, 2, 3 or 4 heteroatoms individually selected from N, O and S, heterocyclyl bonded to L1 through a carbon atom or heterocyclylC1-2alkyl, wherein the heterocyclyl moiety is a 4- to 6-membered non-aromatic ring which comprises 1, 2 or 3 heteroatoms individually selected from N, O and S, and wherein C3-8cycloalkyl, phenyl, heteroaryl and heterocyclyl are optionally substituted by 1, 2 or 3 substituents, which may be the same or different, selected from R7, and wherein when R5 represents C3-8cycloalkyl, C3-8cycloalkylC1-2alkyl, heterocyclyl or heterocyclylC1-2alkyl, the C3-8cycloalkyl or heterocyclyl moiety is optionally substituted by 1 or 2 oxo groups;
• R6 represents hydrogen, C1-6alkyl, C3-6alkenyl, C3-6alkynyl or C1-2haloalkyl;
• R7 represents cyano, halogen, hydroxy, C1-4alkyl, C1-2haloalkyl, C1-4alkoxy, C1-2haloalkoxy, C1-4alkylcarbonyl, C1-4alkoxycarbonyl, aminocarbonyl, C1-4alkylaminocarbonyl or diC1-4alkylaminocarbonyl;
• or
• a salt or an N-oxide thereof.