Objective: A new approach to the synthesis of the cap structure analogue with the correct orientation (Anti-Reverse Cap Analog, ARCA) having a classical structure (dimethylated guanosine dinucleotide 2mGpppG) is proposed. The traditional approach to its preparation is the condensation of activated 7,3′-O-dimethylguanosine-5′diphosphate with guanosine-5′-monophosphate. We suggest to use 3′-O-methylguanosine only for the synthesis of dimethylated guanosine-5′-monophosphate, and to introduce the activated guanosine-5′-diphosphate into the condensation. Methods: Conditions for phosphorylation of 3′-O-methylguanosine were determined to avoid the formation of by-product 3′-O-methyl-5′-deoxy-5′-chloroguanosine-2′-phosphate. Results and Discussion: At the last step of the synthesis, we used activated guanosine-5′-diphosphate (IV) and 7,3′-O-dimethylguanosine-5′monophosphate (VI). Compound (IV) was prepared by a three-step synthesis starting with guanosine. Compound (VI) was prepared by a two-step synthesis starting with 3′-O-methylguanosine. During phosphorylation of 3′-Omethylguanosine an unexpected compound (3′-O-methyl-5′-deoxy-5′-chloroguanosine-2′-phosphate) was formed. The structure of this compound was confirmed by NMR and mass-spectroscopy data. Conclusions: A new approach to the synthesis of ARCA of the guanosine type, methylated at the N7 and 3′ positions of guanosine was proposed. A scheme for the condensation of 7,3′-O-dimethylguanosine-5′-monophosphate and guanosine-5′-diphosphate was implemented. Guanosine 5′-diphosphate was used as activated component. Conditions for phosphorylation of 3′-Omethylguanosine were determined to avoid the formation of by-product 3′-O-methyl-5′-deoxy-5′-chloroguanosine2′-phosphate. ARCA was synthesized in high yield (89% at condensation step). The suggested version of the ARCA synthesis can be easily scaled.