3-Aryl-3-hydroxy-2-methylenepropionic acid esters as fungicides

A compound of formula I:

• wherein:
• R is aryl;
• Ar is heteroaryl;
• Ar1 is a 5 or 6-membered aromatic or heteroaromatic ring;
• X1, X2, and X3 taken individually from H, halogen, alkyl, alkenyl, alkynyl, haloalkyl, alkoxy, haloalkoxy, alkylthio, cyano, nitro;
• aryl or aryloxy or aryloxyalkyl, optionally substituted with halogen, alkyl, haloalkyl, alkoxy, alkyithio, haloalkoxy, cyano, nitro,
• or X1 and X2 or X2 and X3 as an adjacent pair together form the group —Y—W-Z-, where:
• Y and Z are independently oxygen, sulphur, sulphonyl, carbonyl, or CR1R2;
• W is —(CR3R4)p—(CR5R6)q— or sulfonyl;
• R1 and R2 are independently hydrogen, halogen, or alkyl;
• R3 and R4 are independently hydrogen, halogen, alkyl or haloalkyl or together form an oxo group;
• R5 and R6 are independently hydrogen, halogen, alkyl or haloalkyl;
• p is 1 or 2;
• and q is 0 or 1;
• R′ is C1-C4 alkylene optionally substituted with alkyl, haloalkyl, alkoxy, or cyano;
• n is 0 or 1;
• or a salt thereof.