Compound having perfluoroalkyl terminal group and CF2O bonding group, liquid crystal composition and liquid crystal display device

A compound represented by formula (1a):

• in formula (1a),
• R1 is alkyl having 1 to 15 carbons, and in the alkyl at least one —CH2— may be replaced by —O— or —S— and at least one —CH2CH2— may be replaced by —CH═CH—;
• ring A1, ring A2 and ring A3 are independently 1,4-cyclohexylene, 1,4-cyclohexenylene, 1,4-phenylene, tetrahydropyran-2,5-diyl, 1,3-dioxane-2,5-diyl, 2,6,7-trioxabicyclo[2.2.2]octane-1,4-diyl, pyrimidine-2,5-diyl, pyridine-2,5-diyl, naphthalene-2,6-diyl, decahydronaphthalene-2,6-diyl or 1,2,3,4-tetrahydronaphthalene-2,6-diyl, and in these rings at least one hydrogen may be replaced by fluorine or chlorine;
• ring A4 is 1,4-phenylene or naphthalene-2,6-diyl, and in these rings at least one hydrogen may be replaced by fluorine or chlorine;
• Z1 and Z2 are independently a single bond, —CH2CH2—, —CH═CH—, —C≡C—, —COO—, —OCO—, —CH2O—, —OCH2—, —CF2O—, —OCF2— or —CF═CF—;
• o and p are independently 0, 1 or 2, and the sum of o and p is 0, 1 or 2;
• and
• n is an integer from 2 to 10.