2,4,6-Triisopropylbenzenesulfonyl

Triisopropylbenzenesulfonyl)-3-nitro-1,2,4-triazole in the presence of 4-rtiorpholine pyridine-1-oxide was used with advantage as a coupling reagent for a solid-phase (p-alkoxybenzyl ester type resin) synthesis of peptides such as Leu-AIa-Gly-Val-OH or Leu-enkephalinamide (Tyr-Gly-Gly-Phe-Leu-NHs). The overall yield in the latter case was 70%, the purity of the peptide was 85-90%, and racemization was virtually zero.[38]... 

The phosphorylation of the 3 -OH of a 5 -substituted thymidine was achieved with 2,4,6-triisopropylbenzenesulfonyl-3-nitro-1,2,4-triazole [49a]... 

Trimethylbenzenesulfonyl chloride has been shown21 to be much more selective for the monosulfonylation of a vicinal secondary diol (for example, methyl 4,6-O-benzylidene-a-D-gluco-pyranoside) than p-toluenesulfonyl chloride, and, apparently, 2,4,6-triisopropylbenzenesulfonyl chloride exhibits an even higher selectivity.22... 

Triisopropylbenzenesulfonyl azide (trisyl azide), ArSCKN, (1), m. p. 41-43°. Preparation from trisyl chloride and NaN, (80% yield).1... 

In order to use only a stoichiometric amount of alkyllithiums, a modified sulfonylhy-drazone leaving group containing no acidic ortho protons was required, such as 2,4,6-triisopropylbenzenesulfonyl (Trisyl 94) (equation 33). 

In the early solution-phase synthesis of oligonucleotides, coupling of phosphate chesters was used. A mixed 3 -ester with one aryl substituent, usually o-chlorophenyl, was coupled with a deprotected 5 -OH. The coupling reagents used were sulfonyl halides, particularly 2,4,6-triisopropylbenzenesulfonyl chloride.153 The reactions proceed by... 

Triisopropylbenzenesulfonyl hydrazones can be formed from cyclobutanones in very high yield.95... 

NMO NMP Nu PPA PCC PDC phen Phth PPE PPTS Red-Al SEM Sia2BH TAS TBAF TBDMS TBDMS-C1 TBHP TCE TCNE TES Tf TFA TFAA THF THP TIPBS-C1 TIPS-C1 TMEDA TMS TMS-C1 TMS-CN Tol TosMIC TPP Tr Ts TTFA TTN N-methylmorpholine N-oxide jV-methyl-2-pyrrolidone nucleophile polyphosphoric acid pyridinium chlorochromate pyridinium dichromate 1,10-phenanthroline phthaloyl polyphosphate ester pyridinium p-toluenesulfonate sodium bis(methoxyethoxy)aluminum dihydride (3-trimethylsilylethoxy methyl disiamylborane tris(diethylamino)sulfonium tetra-n-butylammonium fluoride f-butyldimethylsilyl f-butyldimethylsilyl chloride f-butyl hydroperoxide 2,2,2-trichloroethanol tetracyanoethylene triethylsilyl triflyl (trifluoromethanesulfonyl) trifluoroacetic acid trifluoroacetic anhydride tetrahydrofuran tetrahydropyranyl 2,4,6-triisopropylbenzenesulfonyl chloride 1,3-dichloro-1,1,3,3-tetraisopropyldisiloxane tetramethylethylenediamine [ 1,2-bis(dimethylamino)ethane] trimethylsilyl trimethylsilyl chloride trimethylsilyl cyanide tolyl tosylmethyl isocyanide meso-tetraphenylporphyrin trityl (triphenylmethyl) tosyl (p-toluenesulfonyl) thallium trifluoroacetate thallium(III) nitrate... 

Although some reactions of electrophilic animation of phosphorus-stabilized anions had already been reported in the literature [5a,d], the first example of such a stereoselective reaction opening access to optically active a-amino phosphonic acids was described in 1992 by Denmark and co-workers [45] and by Jommi and co-workers [46]. Both of these groups used chiral amino alcohols as auxiliaries for diastereo-selective induction in the animating process. Denmark and co-workers chose trisyl azide (2,4,6-triisopropylbenzenesulfonyl azide) as equivalent of NHJ , whereas Jommi and co-workers performed the reaction with DTBAD. 

Treatment of 2,4,6-triisopropylbenzenesulfonyl derivatives 689 with f-BuLi gave the a-lithioenamines 690"4, which reacted with different electrophiles to give the corresponding adducts finally transformed into ketones by easy hydrolysis (Scheme 179). 

One variable that seems to influence the yields in the nucleophilic attack of hydroxyl groups on activated phosphate groups is the relative proportion of these two components in reaction mixtures. A 1 1 ratio of reactants may not be ideal54 if a considerable proportion of the nu-cleotidic component is converted into pyrophosphate, or if, as with activation by 2,4,6-triisopropylbenzenesulfonyl chloride (TPS) further reaction occurs after formation of one phosphoric diester linkage to... 

K. enolate with KHMDS (1.1 equiv) in THF at — 78, C (30min) the Li enolate is similarly prepared with LDA. b TrisylN, = 2,4,6-triisopropylbenzenesulfonyl azide PNBSA = 4-nitroben-zenesulfonyl azide. c Recovered starting material. a Inverse addition of 1 to trisyl azide. e 2 equiv are used. 

Thus, 3, 5 -di-0-(f-butyldimethylsilyl)thymidine (211) is sulfonylated by 2,4,6-triisopropylbenzenesulfonyl chloride (TIPS-CI) to furnish the 4-O-TlPS derivative 212 in 93% yield. Amination with 2-(methylam-ino)ethanol gives rise to 72% of 213 (87TL282I). 

Failure to use 2,4,6-Triisopropylbenzenesulfonyl Azide results in substantial diazo imide formation. However, optimization for the formation of the a-diazo imide compounds can be achieved with NaHMDS and p-nitrobenzenesulfonyl azide, followed by a neutral quench (eq 27). These diazo compounds, however, have failed to demonstrate utility in asymmetric carbenoid chemistry. ... 

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