Linkers for the synthesis of multiple oligonucleotides in seriatim from a single support attachment

A method for the synthesis of a plurality of oligonucleotides comprising the steps of

• (i) forming a first oligonucleotide on a first cleavable link attached to a solid support;
• (ii) attaching to the first oligonucleotide a cleavable linker moiety;
• (iii) forming a second oligonucleotide on the cleavable linker moiety;
• and
• (iv) cleaving the first cleavable link and the cleavable linker moiety to give a plurality of oligonucleotides;
• wherein the cleavable linker moiety is of the Formula (1):
• ##STR35## wherein one or both of A.sup.1 and A.sup.2 is a divalent group of the formula (a):
• ##STR36## R.sup.1 and R.sup.2 are each independently H, optionally substituted alkyl, optionally substituted alkoxy, optionally substituted aryloxy, halogen, cyano, nitro, optionally protected hydroxy, optionally protected oxycarbonyl, optionally protected NH.sub.2 or an electron withdrawing group;
• Y is CH.sub.2, CH.sub.2 CH.sub.2, NH, S or O;
• E is an organic spacer group;
• and any remaining group represented by A.sup.1 or A.sup.2 is of the formula (b):
• ##STR37## wherein n has a value of from 1 to 5;
• the carbon atom marked with an asterisk is attached to an oxygen atom shown in Formula (1);
• and each R.sup.3 independently represents H or optionally substituted alkyl.