mU[5'-O-DMTr-2'-OMe-U](pCyEt)[2'-O-Me-G(iBu)](pCyEt)[2'-OMe-U-3'-CE-Phosphoramidite]-mG-Mu, mU[5'-O-DMTr-2'-OMe-U](pCyEt)[2'-O-Me-G(iBu)](pCyEt)[2'-OMe-U-3'-CE-Phosphoramidite]-mG-Mu,