Maleimide-furanyl compounds that can be used in a general method for preparing maleimide-oligonucleotide derivatives

A compound of formula (I) substantially in exo configuration, or a salt thereof:

• wherein:
• X is a biradical selected from the group consisting of:
• —(CH2)n—*, —(CH2CH2O)nCH2CH2—*,
• n is an integer ranging between 1 and 30;
• * represents the position through which X binds to Y;
• Y is a radical selected from the group consisting of:
• the wavy line representing the place through which Y binds to X;
• PG is a phosphate protecting group;
• and
• R1 and R2 are the same or different to each other and are selected from the group consisting of a C1-C10 alkyl radical and a morpholine radical.

A compound of formula (VII)

• wherein
• X is a biradical selected from the group consisting of:
• —(CH2)n—*, —(CH2CH2O)nCH2CH2—*,
• Y′ is selected from
• the wavy line represents the place by which Y′ binds to X,
• # represents the place through which Y′ binds to the oligonucleotide, and
• P is a solid support.

A compound of formula (VIII)

• wherein
• X is a biradical selected from the group consisting of:
• —(CH2)n—*, —(CH2CH2O)nCH2CH2—*,
• Y′ is selected from
• the wavy line represents the place by which Y′ binds to X, and
• # represents the place through which Y′ binds to the oligonucleotide.