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.
A Direct Synthesis of Allenes by a Traceless Petasis Reaction
作者:Devon A. Mundal、Kelly E. Lutz、Regan J. Thomson
DOI:10.1021/ja301489n
日期:2012.4.4
A one-pot synthesis of allenes by the 2-nitrobenzenesulfonylhydrazide-mediated coupling of hydroxyaldehydes or ketones with alkynyl trifluoroborate salts is reported. This mild process involves in situ formation of a sulfonylhydrazone that reacts with alkynyl trifluoroborates to generate a transient propargylic hydrazide species. Decomposition of this unstable hydrazide via an intermediate monoalkyldiazine
Enantioselective Synthesis of Allenes by Catalytic Traceless Petasis Reactions
作者:Yao Jiang、Abdallah B. Diagne、Regan J. Thomson、Scott E. Schaus
DOI:10.1021/jacs.6b11937
日期:2017.2.8
Allenes are useful functional groups in synthesis as a result of their inherent chemical properties and established reactivity patterns. One property of chemical bonding renders 1,3-substituted allenes chiral, making them attractive targets for asymmetric synthesis. While there are many enantioselective methods to synthesize chiral allenes from chiral starting materials, fewer methods exist to directly
Synthesis of α-Hydroxyallenes by Copper-Catalyzed S<sub>N</sub>2′ Substitution of Propargylic Dioxolanones
作者:Xiaoping Tang、Simon Woodward、Norbert Krause
DOI:10.1002/ejoc.200900226
日期:2009.6
catalytic method for the synthesis of α-hydroxyallenes is described. Efficient SN2′ substitution of propargylic dioxolanones has been achieved with a copper(I)/P(OBu)3 catalyst using Grignardreagents as the nucleophiles. The reaction tolerates a wide variety of propargylic dioxolanones, the corresponding primary and secondary α-hydroxyallenes are obtained in good to excellent yields and excellent diastereoselectivity
Enantioselective Gold(I)-Catalyzed Intramolecular (4+3) Cycloadditions of Allenedienes
作者:Isaac Alonso、Hélio Faustino、Fernando López、José L. Mascareñas
DOI:10.1002/anie.201105815
日期:2011.11.25
Allene‐tethered dienes (1) undergo an intramolecular and highly enantioselective (4+3) cycloaddition when treated with suitable chiral phosphoramidite/gold(I) catalysts (see scheme; Ar=9‐anthracenyl). The reactions provide synthetically relevant [5.3.0] and [5.4.0] fused bicyclic systems 2 with good yields, complete diastereocontrol, and excellent enantioselectivities.
当用合适的手性亚磷酰胺/金(I)催化剂处理时,异戊二烯系二烯(1)会经历分子内高对映选择性(4 + 3)环加成反应(见方案; Ar = 9-蒽基)。反应提供了合成上相关的[5.3.0]和[5.4.0]稠合双环系统2,具有良好的产率,完全的非对映异构控制和优异的对映选择性。