The invention discloses an H-
phosphonate solid-phase
connexon, a preparation method thereof and application of the H-
phosphonate solid-phase
connexon in
solid-phase flow synthesis of circular
nucleic acid. According to the preparation method, a solid-
phase synthesis technology is adopted, exposed amino resin and
succinic anhydride are subjected to a
condensation reaction to obtain a solid-phase carrier with
carboxylic acid, then the solid-phase carrier and 5 '-O-(4, 4'-dimethoxytriphenylmethyl)
deoxycytidine are subjected to an amidation reaction under the assistance of a condensing agent and a condensation activating agent, loading of
deoxycytidine is achieved, and finally H-phosphonation of hydroxyl is completed. The H-
phosphonate solid-phase
linker is obtained. The
linker disclosed by the invention can realize cyclization closure of a linear precursor by utilizing an efficient reaction between an H-phosphonate group and a terminal hydroxyl group of the
linker. The synthesis strategy has the remarkable advantages that the cyclization process can be completed only in 6 hours, and the separation yield reaches up to 73%. The whole process condition is mild, the operation is simple and convenient, the reaction is rapid, and the
gram-scale preparation of the cyclic
nucleic acid can be efficiently realized.