AbstractTreatment of a titanatrane complex with trimethylsilyl chloride and magnesium powder in tetrahydrofuran generated a low‐valent titanium species. This species catalyzed the radical ring opening of epoxides and oxetanes to produce the corresponding less substituted alcohols. The reagent also catalyzed the deallylation and depropargylation of allylic and propargylic ethers, respectively, to provide the parent alcohols.magnified image
A Ruthenium-Catalyzed Hydrosilane-Induced Polymerization of 3-Alkyl-3-hydroxymethyloxetane Derivatives: Facile Access to Functionalized Polyoxetanes by Virtue of Organosilyl Groups
3-(6-Bromo-2-oxahexyl and 8-bromo-2-oxaoctyl)-3-methyloxetanes, and 1,8- and 1,10-bis(3-methyl-3-oxetanyl)-2,7-dioxaoctane and -2,9-dioxadecane were readily prepared in fairly good yields by the reaction of 3-hydroxymethyl-3-methyloxetane (1) with tetra- and hexamethylene dibromides in the presence of a phase-transfer catalyst. The formation of the mono- and disubstituted products depends upon the molar ratios of the dibromide to 1. The optimum reaction conditions for the etherification of 1 with tetramethylene dibromide were searched. The (ω-bromo-2-oxaalkyl)oxetanes were polymerized to give soluble polyoxetanes (\barMn 3500–5500) by cationic ring-opening polymerization. The use of the bisoxetanes, a new cross-linking agent, as a comonomer gave insoluble elastic polyoxetane resins having a pendant bromide at the spacer end.
Highly Enantioselective, Hydrogen-Bond-Donor Catalyzed Additions to Oxetanes
作者:Daniel A. Strassfeld、Zachary K. Wickens、Elias Picazo、Eric N. Jacobsen
DOI:10.1021/jacs.0c03991
日期:2020.5.20
addition of trimethylsilyl bromide (TMSBr) to a broad variety of 3-substituted and 3,3-disubstituted oxetanes. The reaction provides direct and gen-eral access to synthetically valuable 1,3-bromohydrin building blocks from easily accessed achiral precursors. The products are readily elaborated both by nucleophilic substitution and through transition-metal-catalyzed cross-coupling reactions. The enantioselective
Catalytic One-Pot Oxetane to Carbamate Conversions: Formal Synthesis of Drug Relevant Molecules
作者:Wusheng Guo、Victor Laserna、Jeroen Rintjema、Arjan W. Kleij
DOI:10.1002/adsc.201500895
日期:2016.5.19
Oxetanes are versatile building blocks in drug‐related synthesis to induce property‐modulating effects. Whereas related oxiranes are widely used in coupling chemistry with carbondioxide (CO2) to afford value‐added commodity chemicals, oxetane/CO2 couplings remain extremely limited despite the recent advances in the synthesis of these four‐membered heterocycles. Here we report an effective one‐pot
氧杂环丁烷是药物相关合成中的多功能构建基块,可诱导性能调节作用。尽管相关的氧杂环丁烷广泛用于与二氧化碳(CO 2)偶联的化学反应中,以提供增值的商品化学品,但是尽管这些四元杂环的合成取得了新进展,但氧杂环丁烷/ CO 2的偶联仍然极为有限。在这里,我们报告了一种有效的单锅三组分反应(3CR)策略,用于偶联(取代的)氧杂环丁烷,胺和CO 2可以提供具有出色的化学选择性和高收率的各种功能化氨基甲酸酯。该过程由铝基催化剂在相对温和的条件下介导,并且已开发的催化方法可用于两种药学上相关的氨基甲酸酯的正式合成,其中3CR是关键步骤。
Efficient Synthesis of Fluorophosphonylated Alkyles by Ring-Opening Reaction of Cyclic Sulfates
Ring-opening reactions of functionalized 1,2-cyclic sulfates and oxetanes with the phosphonodifluoromethyl carbanion are reported. This approach allows an easy access to fluorinated beta-hydroxyphosphonates that are building blocks in the synthesis of acyclic nucleosides. Synthesis of precursors of nucleoside phosphorylase inhibitors from these alcohols is described.
A practical route from oxetane or thietane to γ‐(thio)butyrolactone via solvated‐proton‐assisted cobalt‐catalyzed carbonylative ring expansion under syngas atmosphere has been established. A wide variety of γ‐(thio)butyrolactones can be afforded in good to excellent yields. The versatility of this method has been well demonstrated in the synthesis of intermediates towards the natural product Arctigenin