Trimethylsilyl ethoxycarbonyl Teoc

The structure of varacin was accomplished by complete spectral characterization of two derivatives (Section 13.17.7.14.2), including an X-ray diffraction analysis of (trimethylsilyl)ethoxycarbonyl (TEOC)-protected varacin 10 (Figure 13) <1994JOC5955>. The pentathiepin ring exists in the expected chair conformation. 

Trimethylsilyl)ethoxycarbonyl Teoc Tetra-n-lmlylarnrnomum chloride and KF-ZHzO in MeCN... 

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. ... 

TEMPO Tentagel Teoc TES Tf TFA TFFH 2,2,6,6-tetramethyl-l-piperidinyloxy PEG-grafted cross-linked polystyrene 2-(trimethylsilyl)ethoxycarbonyl triethylsilane trifluoromethanesulfonyl trifluoroacetic acid tetramethylfluoroformamidinium hexafluorophosphate, [(Me2N)2CF] [P F ]... 

Abbreviations AllocOSu, allyloxycarbonyl-A-hydroxysuccinimide BCIP, 5-bromoA-chloro-3-indolyl Boc, tert-butyloxycarbonyl tBu, tert-butyl DCM, dichloromethane Dde, l-(4,4-dimethyl-2,6-dioxocyclohex-l-ylidene)ethyl Ddz, a, a-dimethyl-3,5-dimethoxyben-zyloxycarbonyl DIC, A,A -diisopropylcarbodiimide DIEA, A,fV-diisopropylethylamine DMF, iV,./V-dimethylformamide FmocOSu, 9-fluorenylmethyloxycarbonyl-AMiydroxysucci-nimide OBOC, one-bead one-compound PBS, phosphate-buffered saline Pmc, 2,2,5,7,8-pentamethylchroman-6-sulfonyl PTH, phenylthiohydantoin RR, relative reactivities Teoc, 2-(trimethylsilyl)ethoxycarbonyl TFA, trifluoroacetic acid Trt, trityl. 

Besides the Fmoc (Section 2.1.1.1.1.3) and the substituted sulfonylethyl groups (Section 2.1.1.1.1.4) that are cleaved by (3-elimination under basic conditions, the A -2-(trimethylsi-lyl)ethoxycarbonyl (Teoc, 43)P 1 and 2-phenyl-2-(trimethylsilyl)ethoxycarbonyl (44)P 1 derivatives (Scheme 21) are readily removed by the action of the fluoride anion, the elimination products of the Grob-type reaction being TMSF, ethene or styrene, and a carbamate which releases carbon dioxide upon aqueous workup. The nature of the cleavage byproducts allows for easy isolation of the free amino compound. 

Scheme 7-60 Synthesis of the esperamicin A, trisaccharide 288 (Danishefsky and co-workers). (PMB, p-methoxybenzyl TEOC, 2-(trimethylsilyl)ethoxycarbonyl).

Under these benzylation reaction conditions, it has been shown that the W-t-butoxycarbonyl (N-Boc) (eq 7) and W-(2-trimethylsilyl)ethoxycarbonyl (N-TEOC) (eq 8) protected amino acid derivatives are converted into their Al-benzyloxycarbonyl (N-Z) analogs. In most cases yields were moderate, but surprisingly the f-butyldimethylsilyloxy and t-butyl ester functions are relatively unaffected by the acidic conditions. 

---