A compound for a use for the purpose of reducing or preventing the appearance of metastases in a patient afflicted with a cancer, corresponding to the general formula below: in which: Y represents an oxygen, sulfur or selenium atom, preferably an oxygen atom, Z represents O, S, Se, NH or a group NR 6, in which R 6 is an optionally substituted aryl or alkyl group, preferably an oxygen atom, R 1 represents a hydrogen atom, an optionally substituted alkyl or cycloalkyl group, or an aryl or heteroaryl group, R 2a represents a hydrogen or halogen atom, an azide group (N 3), a carbonate or dithiocarbonate group, a 1H-[1,2,3]triazolyl group or a group -X-R 2, X representing an oxygen, sulfur or selenium atom, a group NH or NR 7, in which R 7 is an optionally substituted aryl, heteroaryl, alkyl or cycloalkyl group, X preferably representing O or NH, and R 2 representing an optionally substituted aryl, heteroaryl, alkyl or cycloalkyl group, a hydrogen atom, a trichloroacetimidate group (-C(=NH)CCl 3), acyl, formyl, sulfonyl, sulfinyl, tert -butyldiphenylsilyl, allyl, a saccharyl, ester, amide, thioamide or sulfonamide group, or X-R 2 represents a group P R 2' R 6' in which R 2' and R 6' denote, independently of each other, an optionally substituted aryl, heteroaryl, alkyl or cycloalkyl group, OH, alkoxy or aryloxy, R 3 and R 4 represent, independently of each other, an optionally substituted aryl, heteroaryl, alkyl or cycloalkyl group, a hydrogen atom, a trichloroacetimidate, acyl, formyl, sulfonyl, sulfinyl, tert -butyldiphenylsilyl, allyl, ester, amide, thioamide, sulfonamide or saccharyl group, the saccharyl group deriving from sugars or substituted or deoxy sugar analogues, or alternatively R 3 and R 4, taken together, form a divalent radical of formula -R 3 -R 4 -, in which -R 3 -R 4 - preferably represents an isopropylidene, benzylidene, diphenylmethylidene, cyclohexylmethylidene group, optionally substituted, preferably a 4-methoxybenzylidene group, or a linear alkylene group, preferably the ethylene group, R 5 represents a hydrogen atom or a hydrocarbon-based group comprising one or more heteroatoms preferably chosen from oxygen, sulfur and nitrogen, better still oxygen. Y represents an oxygen, sulfur or selenium atom, preferably an oxygen atom, Z represents O, S, Se, NH or a group NR 6, in which R 6 is an optionally substituted aryl or alkyl group, preferably an oxygen atom, R 1 represents a hydrogen atom, an optionally substituted alkyl or cycloalkyl group, or an aryl or heteroaryl group, R 2a represents a hydrogen or halogen atom, an azide group (N 3), a carbonate or dithiocarbonate group, a 1H-[1,2,3]triazolyl group or a group -X-R 2, X representing an oxygen, sulfur or selenium atom, a group NH or NR 7, in which R 7 is an optionally substituted aryl, heteroaryl, alkyl or cycloalkyl group, X preferably representing O or NH, and R 2 representing an optionally substituted aryl, heteroaryl, alkyl or cycloalkyl group, a hydrogen atom, a trichloroacetimidate group (-C(=NH)CCl 3), acyl, formyl, sulfonyl, sulfinyl, tert -butyldiphenylsilyl, allyl, a saccharyl, ester, amide, thioamide or sulfonamide group, or X-R 2 represents a group P R 2' R 6' in which R 2' and R 6' denote, independently of each other, an optionally substituted aryl, heteroaryl, alkyl or cycloalkyl group, OH, alkoxy or aryloxy, R 3 and R 4 represent, independently of each other, an optionally substituted aryl, heteroaryl, alkyl or cycloalkyl group, a hydrogen atom, a trichloroacetimidate, acyl, formyl, sulfonyl, sulfinyl, tert -butyldiphenylsilyl, allyl, ester, amide, thioamide, sulfonamide or saccharyl group, the saccharyl group deriving from sugars or substituted or deoxy sugar analogues, or alternatively R 3 and R 4, taken together, form a divalent radical of formula -R 3 -R 4 -, in which -R 3 -R 4 - preferably represents an isopropylidene, benzylidene, diphenylmethylidene, cyclohexylmethylidene group, optionally substituted, preferably a 4-methoxybenzylidene group, or a linear alkylene group, preferably the ethylene group, R 5 represents a hydrogen atom or a hydrocarbon-based group comprising one or more heteroatoms preferably chosen from oxygen, sulfur and nitrogen, better still oxygen.