Efficient Synthesis of 3-Chloromethyl-2(5<i>H</i>)-furanones and 3-Chloromethyl- 5,6-dihydropyran-2-ones via the PdCl<sub>2</sub>-Catalyzed Chlorocyclocarbonylation of 2,3- or 3,4-Allenols
作者:Xin Cheng、Xuefeng Jiang、Yihua Yu、Shengming Ma
DOI:10.1021/jo8015677
日期:2008.11.21
was formed between the center carbon atom of the allene moiety and the hydroxyl oxygen, which was established by the X-ray single crystal diffraction study of gamma-lactone 3p. The highly opticallyactive 3-chloromethyl-2(5H)-furanones could be easily prepared from the readily available opticallyactive 2,3-allenols. A mechanism for this reaction was proposed.
demonstrated a very generalmethod for the preparation of essentially any terminal 2,3-allenol from the corresponding alkynols, which may be easily available from propargylic alcohols by alkylation, or from terminal alkynes by deprotonation and 1,2-addition with aldehydes or ketones, and subsequent base-catalyzed triple-bond migration. We have demonstrated a very generalmethod for the preparation of essentially
Addition of Chloroprene Grignards to Aromatic Aldehydes: Synthesis of Homoallenyl Alcohols
作者:Arne G. A. Geissler、Bernhard Breit
DOI:10.1021/acs.orglett.1c00527
日期:2021.4.2
A general procedure for the one-pot synthesis of racemic homoallenyl alcohols from the corresponding aldehyde and chloroprene-derived Grignards is described. Employing bis[2-dimethylaminoethyl]ether (BDMAEE) as an additive at low temperatures shifts the selectivity of the chloroprene Grignard addition to aldehydes such that it is almost exclusive toward allene formation. In a set of follow-up experiments
An Efficient Synthesis of Terminal Allenes from Terminal 1-Alkynes
作者:Jinqiang Kuang、Shengming Ma
DOI:10.1021/jo802391x
日期:2009.2.20
We have developed a modified method for the synthesis of terminalallenesfromterminal 1-alkyne: The reaction of 1-alkynes with 1.8 equiv of Cy2NH and 2.5 equiv of paraformaldehyde mediated by CuI (0.5 equiv) in refluxing dioxane may produce terminalallenes in much higher yields than the previously reported protocol and many functional groups such as mesylate, hydroxyl group, ether, amide, etc. may
Rhodium-Catalyzed Diastereoselective Cyclization of Allenyl-Sulfonylcarbamates: A Stereodivergent Approach to 1,3-Aminoalcohol Derivatives
作者:Pierre A. Spreider、Alexander M. Haydl、Marc Heinrich、Bernhard Breit
DOI:10.1002/anie.201609366
日期:2016.12.12
described and it provides selective access to 1,3‐aminoalcohol derivatives, scaffolds found in bioactive compounds. The reaction is compatible with a large range of different functional groups, thus furnishing products with high diastereoselectivities and yields. Moreover, multigram scale reactions, as well as the application of suitable product transformations were demonstrated.