A simple and highly chemoselective desilylation of tert-butyldimethylsilyl ethers

Lee, Adam Shih‐Yuan; Yeh, H. C.; Tsai, Ming-Hung

doi:10.1016/0040-4039(95)01423-f

Cited by 43 publications

(14 citation statements)

References 14 publications

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“…using mineral acids. In-situ formation of H + from halocarbons under ultrasound irradiation is well known (Scheme 3) [26][27][28][29][30].…”

Section: Dehydration Reactionsmentioning

confidence: 99%

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Ultrasound in Synthetic Organic Chemistry

Schmidt¹

2005

Advances in Organic Synthesis

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“…using mineral acids. In-situ formation of H + from halocarbons under ultrasound irradiation is well known (Scheme 3) [26][27][28][29][30].…”

Section: Dehydration Reactionsmentioning

confidence: 99%

“…Scheme(27). Epoxidation of olefins.The epoxidation of α,β-unsaturated ketones can be carried out under low power ultrasound irradiation affording very high yields in one-hour reaction time at room temperature[99].…”

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confidence: 99%

Ultrasound in Synthetic Organic Chemistry

Schmidt¹

2005

Advances in Organic Synthesis

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“…In the first step, ultrasound irradiation promotes the formation of HCl [10][11][12][13][14][15] (see Scheme 3):…”

Section: Mechanismmentioning

confidence: 99%

“…These results could be explained by the formation of a small amount of HCl during the sonication of CHCl 3 followed by dehydration of the HMA. The formation of HX (X = Cl, Br) from halocarbons is well known [11][12][13][14][15] (see Scheme 2).…”

Section: Introductionmentioning

confidence: 99%

Dehydration reaction of hydroxenin monoacetate in carbon tetrachloride and an aliphatic alcohol under ultrasound irradiation

Aquino¹,

Bonrath²,

Schmidt³

et al. 2005

Ultrasonics Sonochemistry

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A new method for the preparation of an E/Z mixture of vitamin A acetate from hydroxenin monoacetate is described. This two-step reaction was studied by changing the reaction parameters (reaction temperature, ultrasound power, and reaction time) and the alcohol used. This approach consists of the dehydration reaction of hydroxenin monoacetate under ultrasound irradiation in CCl4 and an aliphatic alcohol under an inert atmosphere. The formation of small amounts of HCl from CCl4 and an aliphatic alcohol under ultrasound irradiation is followed by the dehydration reaction of hydroxenin monoacetate. An E/Z mixture of vitamin A acetate was obtained resulting in the desired pentaenes. Some ethers derivatives were also formed as by-products, isolated and characterized. Study of the reaction mechanism is also reported here.

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“…Recently, the removal of TBS and THP groups by chemical oxidations has received much attention [3][4][5][6][7]. Although a variety of new methods to remove TBS and THP groups have been developed [8][9][10][11][12][13][14][15][16][17], most of them suffer from one or more drawbacks such as the need for large amounts of reagents, harsh reaction conditions, and cumbersome workup. Therefore, new methods are still in demand.…”

mentioning

confidence: 99%

Catalytic removal of tert-butyldimethylsilyl (TBS) and tetrahydropyranyl (THP) groups from protected alcohols by NO+BF4 − in methanol

Wang

et al. 2010

Chin. Sci. Bull.

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An effective, catalytic method has been developed to remove TBS and THP groups from protected alcohols. TBS and THP ethers were selectively cleaved using a catalytic amount of NO + BF 4 -(5 mol%) in methanol at room temperature. deprotection, TBS and THP ether, NO + BF 4 -, catalytic Citation: Wang J T, Wu W T, Xu Y F, et al. Catalytic removal of tert-butyldimethylsilyl (TBS) and tetrahydropyranyl (THP) groups from protected alcohols by NO + BF 4 -in methanol.As they attempt to synthesize increasingly complicated molecules, chemists need to develop more effective methods to attach and remove protecting groups. Among them, tert-butyldimethylsilyl (TBS) and tetrahydropyranyl (THP)[1] ethers are frequently used to protect hydroxyl groups. These ethers are easily cleaved by fluoride ion [1,2] and aqueous acids [1]. Recently, the removal of TBS and THP groups by chemical oxidations has received much attention [3][4][5][6][7]. Although a variety of new methods to remove TBS and THP groups have been developed [8][9][10][11][12][13][14][15][16][17], most of them suffer from one or more drawbacks such as the need for large amounts of reagents, harsh reaction conditions, and cumbersome workup. Therefore, new methods are still in demand. In this paper, we report a catalytic and effective method to remove TBS and THP groups under mild reaction conditions, allowing other functional groups to survive. Nitrosonium ion (NO + ) is predicted both as a single electron oxidant with a reduction potential of E 0 red = 1.50 V (vs. SCE) [18,19], and as a strong electrophile. Our interest [20][21][22][23] in NO + has promoted us to use it for the cleavage of TBS and THP ethers. We found that a catalytic amount of NO + BF 4 -(5 mol%) in methanol effectively removes TBS *Corresponding author (email: nlaoc@lzu.edu.cn) and THP groups from protected alcohols (Scheme 1). Results are summarized in Tables 1 and 2. A typical procedure for catalytic deprotection of TBS and THP ethers was performed as follows: A catalytic amount of NO + BF 4 -(0.05 mmol) was added to a solution of TBS or THP ether (1 mmol) in methanol (5 mL). The resulting mixture was stirred at room temperature, and the reaction was monitored by TLC. After the completion of the reaction, the solvent was removed under vacuum. The residue was purified by column chromatography on silica gel to afford the corresponding alcohol or phenol in various yields.Various TBS ethers with different steric and electronic environment were synthesized and subjected to our method. In the case of TBS ethers (entries 1-10, Table 1), reactions proceeded rapidly and protecting groups were removed in high yield. Some TBS ethers (entries 11-14, Table 1) required longer reaction time to reach satisfactory yields, Scheme 1 Catalytic removal of TBS and THP groups from protected alcohols by NO + BF 4 -.

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A simple and highly chemoselective desilylation of tert-butyldimethylsilyl ethers

Cited by 43 publications

References 14 publications

Ultrasound in Synthetic Organic Chemistry

Ultrasound in Synthetic Organic Chemistry

Dehydration reaction of hydroxenin monoacetate in carbon tetrachloride and an aliphatic alcohol under ultrasound irradiation

Catalytic removal of tert-butyldimethylsilyl (TBS) and tetrahydropyranyl (THP) groups from protected alcohols by NO+BF4 − in methanol

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