TBDPS ethers

Benzyl, allyl, methyl, THP, TBDMS, and TBDPS ethers are all stable to these conditions. A primary MEM group could be selectively removed in the presence of a hindered secondary MEM group. 

TsOH, MeOH, 25°, 1 h, 94% yield.TBDPS ethers are not affected by these conditions. ... 

LiAlH4 has resulted in the cleavage of a TBDPS group, but this is not general. TBDPS ethers are generally not affected by LiAlH4. 

NaH, HMPA, 0°, 5 min H2O, 83-84% yield. These conditions selectively cleave a TBDPS ether in the presence of a t-butyldimethylsilyl ether. 

ZnBr2, MeOH, 100% yield. TIPS and TBDPS ethers are stable to these conditions. 

Methanol, CCI4, ultrasonication, 40-50°, 90-96% yield." Phenolic TBDMS and TBDPS ethers are stable. 

AcBr, CH2CI2, it, 20 min, 90% yield. These conditions convert the TBDMS ether into the acetate. Benzyl and TBDPS ethers are stable, except when SnBr2 is included in the reaction mixture, in which case these groups are also converted to acetates in excellent yield. ... 

BF3 Et20)-Bu4N F. This reagent is selective for TBDMS ethers in the presence of TIPS and TBDPS ethers. ... 

The TBDPS ether has been used for the monoprotection of a catechol (TBDPSCl, Im, DMF, 5 h, 83% yield) or simple phenol protection. It is cleaved with Bu4N F- (THF, 94% yield). ... 

M HCl, EtOAc, 25°, 30 min, 96% yield. With MeOH as the solvent, a diphenylmethyl ester is not affected. The combination of HCl/EtOAc leaves TBDMS and TBDPS ethers and t-butyl esters and nonphenolic ethers intact during BOC cleavage, but 5 -BOC derivatives are cleaved. 

TBDMS ethers. 95.% TBDMSC1.93.94.101.120. 121 TEDMSOTf, 93.120 TBDPS ethers. 95... 

Z-isomers of 2-pentenyloxy ethers show modest stereoselectivity, but the fi-ethers show no stereoselectivity.26 Trisubstituted allylic TBDPS ethers show good stereoselectivity.27... 

C3 and C26 TES ethers and the C23 TBDPS ether, and spontaneous C-ring closure to furnish bryostatin 7 in 60 % yield (Scheme 5.14). 

A highly selective and mild procednre for cleavage of TBDMS ethers to the corresponding alcohols by nsing Oxone was developed recently. Interestingly, it has been found that feri-butyldiphenylsilyl (TBDPS) ether and certain acid-labile gronps snch as tetrahydropy-ranyl (THP), A-Boc or a carbon-carbon donble bond remain nnaffected under the reaction conditions (eqnation 69) . ... 

Silyl ethers that have been used in solid-phase synthesis include TES, TIPS, TBS, and TBDPS ethers. Polystyrene-bound phenols can be converted into TIPS ethers by treatment with TIPS-OTf/imidazole in DMF for 5 min [105], These silyl ethers are stable towards bases and weak acids, but can be selectively removed by treatment with TBAF (Entries 6 and 8, Table 7.8) or pyridinium hydrofluoride (THF, 25 °C, 15 h [24,75,106]). 

The TBDPS ether remains unaffected, while the more acid-sensitive TMS ether is hydrolysed and the corresponding alcohol is oxidized to ketone. 

Initial work involved the functionalisation of C as a TBDPS ether (as in 59a) However, this proved to be incompatible with our overall approach. An alternative, and somewhat more direct strategy involved the incorporation of a halogen at C from the outset. This was expected to be entirely compatible with subsequent steps, conveniently undergoing transformation into the corresponding triphenylphosphonium salt at a later stage. Initially, the bromide 59b was chosen and indeed was found to be admirably compatible with the ensuing chemistry. However, during... 

Silyl ethers, such as TMS, triethylsilyl (TES), triisopropylsilyl (TIPS), lerl-butyldi-methylsilyl (TBS), and terl-butyldiphenylsilyl (TBDPS) ethers (Scheme 2.6), are frequently used in carbohydrate chemistry due to their unique reactivity and steric effect (see Section 2.4.1) [1, 2], These groups are typically introduced onto the molecule by treatment with the corresponding silyl halide or triflate (OTf) and a base, such as Et3N, pyridine, 2,6-lutidine, or imidazole. 

The total synthesis of mniopetal E (5) was achieved in a six-step sequence from the cycloadduct 125 (Scheme 21). The treatment of 125 with trifluoromethanesulfonic anhydride (Tf20) afforded triflate 129. Elimination of trifluoromethanesulfonic acid to introduce a double bond was accomplished in 2,6-lutidine at 100 °C, giving 130 in 84% yield. Deprotection of TBDPS ether was followed by Parikh-Doering oxidation of the resulting 131 by the same procedure used in the case of 127. Taking advantage of the electron-rich double bond between C-l... 

Reaction of 4-(pivaloyloxy)benzaldehyde with the E -crotyldiisopinocampheylbo-rane d19E gave the corresponding homoallylic alcohol 22 in a 98 2 enantiomeric ratio. After protection of the alcohol as a tert-butyldiphenylsilyl (TBDPS) ether, the alkene was subjected to ozonolysis to provide the 3-hydroxy aldehyde 23. 

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