The 4â Methylthioâ 1â Butyl Group for Phosphate/Thiophosphate Protection in Oligodeoxyribonucleotide Synthesis

The detailed preparation of deoxyribonucleoside phosphoramidites functionalized with a 4â methylthioâ 1â butyl group for P(III) protection is described, along with the incorporation of these phosphoramidites into DNA oligonucleotides via solidâ phase techniques. The versatility of the thermolabile 4â methylthioâ 1â butyl phosphate/thiophosphateâ protecting group is exemplified through its facile removal from oligonucleotides under neutral conditions or under standard basic conditions. The sulfonium salt that is produced during the thermolytic deprotection of oligonucleotides did not alter DNA nucleobases or desulfurize phosphorothioate diesters to a significant extent.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/143609/1/cpnc0311.pd