Ferf-butyldiphenylsilyl

PPTS, Pyridinium p - toluene s u I fo n ate SE, 2-Trimethylsilylethyl TBDMS, ferf-Butyl-dimethylsilyl TBDPS, ferf-Butyldiphenylsilyl TEMPO, 2,6,6-Tetramethyl-l-piperidi-nyloxy Tf, Trifluoromethanesulfonyl THF, Tetrahydrofuran THP, Tetrahydropyran TIPDS, l,l,3,3-Tetraisopropyl-l,3-disiloxanyl TMS, Trimethylsilyl. 

V"-(Fluoren-9-ylniethoxycarbonyl)-V7 -(ferf-butoxycarbonyl)-5-0-[6-0-(ferf-butyldiphenylsilyl)-3,4-0-... 

A highly selective and mild procedure for cleavage of TBDMS ethers to the corresponding alcohols by using Oxone was developed recently. Interestingly, it has been found that ferf-butyldiphenylsilyl (TBDPS) ether and certain acid-labile groups such as tetrahydropy-ranyl (THP),, V-Boc or a carbon-carbon double bond remain unaffected under the reaction... 

The selective cleavage of the IV-t-butoxycarbonyl group in the presence of TBDMS (t-butyldimethylsilyl) (selective only when the protected alcohol was phenolic) or TBDPS (ferf-butyldiphenylsilyl) (completely selective) ethers can be achieved68 using a saturated solution of HC1 in ethyl acetate. 

Ar Bn Boc Bz Cbz Et /-Bu i-Pr Me n-Bu n-Pr Ph s-Bu f-Bu TBDPS TBS Tf TMS aryl benzyl te rf-butoxy c arbonyl benzoyl benzyloxycarbonyl ethyl isobutyl isopropyl methyl n-butyl n-propyl phenyl sec-butyl ferf-butyl ferf-butyldiphenylsilyl ferf-butyldimethylsilyl trifluoromethanesulfonyl trimethylsilyl... 

SCHEME 4.5 1,2-Migration in the stereoselective synthesis of 1, 2-tram (amino)-glyco-sides and 2-deoxyglycosides as reported by (a) Danishefsky, (b) Yu, and (c) Lowary. Ac, acetyl All, allyl Bn, benzyl Bz, benzoyl DTBMP, 2,6-di-fert-butyl-4-mcthyl pyridine TBDPS, ferf-butyldiphenylsilyl THF, tetrahydrofuran TIPS, triisopropylsilyl Tol, 4-tolyl. 

FIGURE 10.1 Some monosaccharide building blocks used in the assembly of (a) HA, (b) CS, and (c) heparin/HS showing the array of protecting groups. All, allyl Bn, benzyl Bz, benzoyl Fmoc, 9-fluorenylmethoxycarbonyl Lev, levulinyl NAP, 2-naphthylmethyl PBB, p-bromobenzyl Phth, phthaloyl PMB, / -methoxybenzyl PMP, p-methoxyphenyl TBDPS, ferf-butyldiphenylsilyl TBS, ferf-butyldimethylsilyl TCA, trichloroacetyl TDS, dimethylthexylsilyl Tol, 4-tolyl. 

SCHEME 14.15 Synthesis of a type IV lipoteichoic acid by Schmidt et al. TBDPS, ferf-butyldiphenylsilyl. 

First conversion of primary alcohol 3 to the ferf-butyldiphenylsilyl ether 15 occurs. In the field of silyl ethers the TPS group as well as the triisopropylsilyl (TIPS) group are the most stable protecting groups against a large variety of reaction conditions - consequently they are frequently used in organic synthesis (see Chapter 2). ... 

In this section, the formation and cleavage of eight protecting groups for alcohols and phenols are presented acetate acetonides for diols benzyl ether para-methoxybenzyl (PMB) ether methyl ether methoxymethylene (MOM) ether ferf-butyldiphenylsilyl (TBDPS) silyl ether and tetrahydropyran (THP). 

Steroid 2 was prepared from dehydroisoandrosterone in a total of 12 steps and 10% yield (Scheme 4) [10]. The stereochemistries involved in the transformations were completely controlled by the steroid substrates themselves (4 —> 5, 5 —> 6, 8 —> 9, 9 —> 2). The 3-OH was hrst protected by a ferf-butyldiphenylsilyl (TBDPS) group because the TBS protection was found to be susceptible in the ene reaction (4 —> 5). Then, because it was found in a model reaction that the conditions for removal of the 3-OTBDPS group resulted in considerable migration and cleavage of the Ac and MBz groups in the sugar moiety of the target molecule (1), the 3-OTBDPS was transferred into TBS protection (7 8). 

TMS TBS TBDPS trimethylsilyl ferf-butyldimethylsilyl ferf-butyldiphenylsilyl... 

The 2-(methyldiphenylsilyl)ethyl (DPSME) group was used to protect a phosphate in a synthesis of Lysobisphosphatidic Acid [Scheme 7.40]. The phosphate protection was intr uced by a phosphite triester approach to give the symmetrical phosphate 40.2. The two isopropylidene groups were removed by acid hydrolysis without harm to the phosphate and the resultant diols selectively protected on their less hindered termini with ferf-butyldiphenylsilyl groups. Acylation of the remaining secondary hydroxyls with oleic anhydride a orded the diester 40J, whereupon the silyl protecting groups were removed with... 

TBDPS ferf-butyldiphenylsilyl TPAP tetra-n-propylammonium perruthenate... 

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