Photocleavable linker molecules with diarylsulphide backbone for transient bioconjugate synthesis

A photocleavable compound of formula I

• wherein A is —CH2—, —CH2—CH2—, —CH(CH3)— or —CH(CH3)—CH2—,
• R3 is H, a methyl group or an ethyl group,
• R2 is a phosphoramidite, H-phosphonate, phosphate diester or phosphate triester, wherein, when R2 is a phosphate diester of the formula —O—P(O)-(OR4)-(OH), R4 is an alkyl or substituted alkyl or a nucleoside or an oligonucleotide, and
• wherein, when R2 is a phosphate triester of the formula —O—P(O)-(OR4)-(OR5), R4 and R5 each is alkyl or substituted alkyl or a nucleoside or an oligonucleotide or together form an internucleotide moiety of an oligonucleotide,
• R1 is a phenylcarboxylic amide, and
• wherein a functional group is bound via the amino group to the phenylcarboxylic amide.