Teoc group

The Teoc group is introduced onto pyrroles, or indoles with 4-nitrophenyl 2-(tri-methylsilyl)ethyl carbonate and NaH in 61-64% yield. The Teoc group can be removed with Bu4N F in CH3CN. ... 

The Teoc group is cleaved by TBAF in THF at room temperature in less than an hour232 Silyl ethers are incompatible as shown in a late step of a synthesis... 

A panoply of protecting groups was enlisted in the synthesis of Damavaricin by Roush and co-workers.242 Here we show 2 steps [Scheme 8.100] towards the end of the synthesis in which a Teoc group and a 2-(trimethylsilyl)ethyl ester were cleaved simultaneously with TAS-F to liberate an amino group and a carboxyl group that served as partners in a macrolactamisation reaction. 

Scheme 8,107 shows how a Teoc group was appended to an amino acid using 2-(trimethylsilyl)ethyl 1-benzotriazolyl carbonate.243 The methyl ester group could be hydrolysed selectively in the presence of the Teoc group using 13 equivalents of lithium hydroxide in aqueous (erf-butyl alcohol at 0 °C for 30 min. 

This group was developed as a UV-active group for carbohydrate synthesis. It is introduced with the chloroformate (DMAP, CH2Cl2.rt, 15 h, 59-66% yield). As with the Teoc group, it is cleaved with TBAF, which can be done in the presence of a variety of esters. It can not be cleaved in the presence of the Fmoc group even with AcOH buffered TBAF. ... 

Teoc group is competitive with the BOC group. The use of fluoride reagents in this case resulted in partial loss of the boronate. Cleavage of BOC group at this position was unsuccessful. 

The Psoc group was developed for the protection of amino acids. Its stability and orthogonality are similar to that of the Teoc group hut it is more susceptible to cleavage with TBAF than is the Teoc group and can he cleaved with trifluoroacetic acid. It is introduced with the 4-nitrophenyl carbonate (72-99% yield) and cleaved with TBAF in CH2CI2 (no yield reported). The liability that this group has is its chirality. ... 

Trimethylsilyl)ethoxycarbonyl (Teoc) groups have been used to protect amine functionalities (eq 16). Using a mixture of tetra-n-butylammonium chloride and KF-2H20 deprotects the Teoc group. iV-Debenzylation and concurrent protection as N-Teoc results when tertiary )V-benzylamines are treated with 2-(trimethylsilyl)ethylchloroformate. ... 

Alternative reagents for the introduction of the Teoc group include 2-(trimethylsilyl)ethyl chloroformate (3 X = Cl), trimethylsilylethyl azidoformate (3 X = Ns), trimethylsilylethyl methoxyvinyl carbonate (4), trimethylsilylethyl 4-nitrophenyl carbonate (5), and the aminoxy carbonates (6). Of these, only the 4-nitrophenyl carbonate (5) is commercially available. The carbonate (5) has been used to block NH groups in amino acids and indoles. ... 

TBDMS) ether in the presence of a trimethylsilylethyl carbamate (eq 2). For a discussion of alternative reagents for the introduction of the Teoc group, see 2-(trimethylsilyl)- 0- OMe... 

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