Selective Monoalkylation of Acyclic Diols by Means of Dibutyltin Oxide and Fluoride Salts.

Syntheses of monohydroxy benzyl ethers of polyols: tri-O-benzylpentaerythritol and other highly benzylated derivatives of symmetrical polyols

“…It appears that the second substitution is faster than the first, while the third is slower than the second, probably for steric reasons. Nagashima and Ohno reported that benzylation of glycerol in DMF with 1 equiv of the benzylating agent using cesium fluoride as catalyst gave about equal amounts of the mono and disubstituted products, 21 in agreement with our observations.…”

“…[15][16][17] They can be prepared by reaction of diols with dibutyltin oxide in refluxing methanol or by refluxing in benzene or toluene with azeotropic removal of water. They have served as convenient intermediates for the formation of monobenzyl ethers from diols or polyols by reaction with benzyl bromide either in benzene or toluene in the presence of added nucleophiles, such as tetrabutylammonium bromide, 18,19 or in dimethylformamide in the presence of cesium fluoride 20,21 to give good yields of monosubstituted products. David demonstrated that the bis(dibutylstannylene) acetal of pentaerythritol can serve as an intermediate for making the dibenzyl derivative.…”

Regioselective synthesis of long-chain ethers and their sulfates derived from methyl β-d-galactopyranoside and derivatives via dibutylstannylene acetal intermediates

“…It was found that the reactions of the long-chain alkyl bromides with dibutylstannylene acetals using the conditions of Danishefsky and Hungate 27 and by Nagashima and Ohno, 28,29 that is, in DMF with added cesium fluoride, gave somewhat better yields than the first conditions developed for alkylation reactions of dibutylstannylene acetals by Veyrières and co-workers, 22 that is, in benzene or toluene with added tetraalkyl ammonium halides (in Table 1, compare entry 2 with entry 4 or 8). Reactions of dibutylstannylene acetals with active alkyl halides, methyl iodide, benzyl iodide, and benzyl bromide occur in DMF with added cesium fluoride at rt; 29 the less active alkyl bromides used here react very slowly at room temperature (see entry 3).…”

A novel application of tin-based alkoxide anion for deacetylation

“…To test this notion, a series of simple aromatic and aliphatic acetates (containing an aromatic moiety for convenience of monitoring the reaction progress by TLC under UV light) were treated with 2,2-dibutyl- [1,3,2]dioxastanninane 1 in the presence of CsF (Table 1), a nucleophile that is believed to promote dibutylstannylene acetal-based reactions [10]. 2,2-dibutyl- [1,3,2]dioxastanninane 1 was readily prepared in situ by treating dibutyltin oxide and 1,3-propanediol in refluxing methanol for 3 h followed by sequential removal of methanol and any remaining water as a benzene azeotrope.…”

“…The resulting 1 was used for deacetylation without further purification. Both aromatic (substrates 2-7) and aliphatic (substrates 8-13) acetates react rapidly with 1 and CsF in DMF at room temperature to afford the corresponding alcohols (2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13) in excellent yields after silica gel column chromatography. TLC analysis indicated that the reaction was essentially complete within 1 h. The electron withdrawing and donating groups, as well as sterically crowded substituents on the aromatic rings have no apparent effect on the deacetylation reaction.…”