Optimization and Mechanistic Analysis of Oligonucleotide Cleavage from Palladium-Labile Solid-Phase Synthesis Supports
Pd(0)-labile solid-phase synthesis supports have been used to produce oligonucleotides containing 3′-alkyl carboxylic acid and 3′-hydroxy termini in quantitative yields. Optimization of the cleavage reaction conditions using tetrabutylammonium formate buffer resulted in quantitative yields of oligonucleotides using 4 molar equiv of Pd2(dba)33·CHCl3 in 1 h at 55 °C. A proton source facilitates cleavage of the oligonucleotide from the supports. Trace amounts of water, acting as a nucleophile on the η3-complex, presumably preventing back biting by the initially released oligonucleotide, are required to obtain reproducibly high yields of cleaved oligonucleotides during a 1 h reaction. The previously observed lability of β-cyanoethyl groups to the Pd(0) conditions has been examined using a mononucleotide substrate. Cleavage of the β-cyanoethyl group was shown to proceed to the exclusion of other alkyl groups. A mechanism involving initial insertion by Pd(0) into the carbon-oxygen bond of the β-cyanoethyl group is suggested to account for the cleavage of this group.
Greenberg, Marc M.,Matray, Tracy J.,Kahl, Jeffrey D.,Yoo, Dong Jin,McMinn, Dustin L.
Synthesis of 3'-functionalized oligonucleotides on a single solid support
Oligodeoxyribonucleotides tethered with an amino-, carboxy,- amidocarbonyl-, or mercaptoalkyl spacer arm at 3'-terminus were obtained by assembling the chains on a modified aminoalkyl-CPG (1) and releasing them with appropriate reagents.
Stepwise solid-phase synthesis of peptide-oligonucleotide conjugates on new solid supports
Several peptide-oligonucleotide and peptide-(oligonucleotide phosphorothioate) conjugates were synthesized on new solid supports. These supports are designed to link the 3'-terminus of an oligonucleotide to the C- end of a peptide via a phosphodiester or
Antopolsky, Maxim,Azhayev, Alex
p. 2130 - 2140
(2007/10/03)
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