Tetrazole coupling process

In 2013, a combined effort by groups from Germany and France saw the application of tetrazole precursors in the photoinduced tetr2izole-ene coupling process leading to nitrile-butadiene rubber with molar masses up to 48 kDal [95]. The reversible addition-fragmentation chain transfer (RAFT) procedure was employed, using a tetrazole-functionalized trithiocarbonate. 

The [3+2] cycloaddition of azides to double and triple bond systems has found considerable interest over the last couple of years. The reaction can either be performed under thermal conditions or by copper(i) catalysis <2001AG(E)2004, 2002AG(E)2596>. In an attempt to broaden the chemistry of such cycloaddition processes, Sharpless et al. reported the generation of tetrazole derivatives 61 by an intramolecular process (Scheme 12). In... 

The chemistry of the phosphoramidite coupling has been thoroughly studied, and the use of l//-tetrazole (115) as an activating agent for the reaction (Fig. 2.17) with support-bound 2.52 allows the SPS of long ON sequences with high yields (116). The use of stable and easily handled A,A-diisopropylphosphoramidites such as 2.53 (117,118) is important for the automation of the process (119). The base-labile... 

Figure 2.5 Solid Phase DNA Synthesis. 5 -dimethoxytrityl (DMT)-deprotection of resin bound 3 -terminal deoxynucLeoside residue is effected with trichloroacetic acid (TCA) (mechanism shown) Thereafter the first coupling reaction is enabled by phosphoamidite activation with tetrazole (mechanism shown) followed by oxidation of the newly formed diester linkage to a phosphodiester link. The process of 5 -DMTr deprotection, phosphoramidite coupling and then diester oxidation, continues for as many times as required (n-times), prior to global deprotection and resin removal under basic conditions.

---