Lewis-Acid-Promoted Ligand-Controlled Regiodivergent Cycloaddition of Pd-Oxyallyl with 1,3-Dienes: Reaction Development and Origins of Selectivities
作者:Weiwei Chai、Qingyang Zhou、Wenna Ai、Yin Zheng、Tianzhu Qin、Xiufang Xu、Weiwei Zi
DOI:10.1021/jacs.0c13412
日期:2021.3.10
for catalytic (3 + 2) cycloaddition reactions of palladium-oxyallyl species with alkenes. However, because C–O bond formation is kinetically favored, the (3 + 2) cycloadditions achieved to date have involved C–O reductive elimination. We herein report a method of lithium triflate-promoted (3 + 2) cycloaddition reactions of palladium-oxyallyl species with 1,3-dienes that proceed via a pathway terminated
Iron(III)/O<sub>2</sub>-Mediated Regioselective Oxidative Cleavage of 1-Arylbutadienes to Cinnamaldehydes
作者:Amit Bhowmik、Rodney A. Fernandes
DOI:10.1021/acs.orglett.9b03562
日期:2019.11.15
environmentally benevolent regioselective oxidative cleavage of 1-arylbutadienes to cinnamaldehydes mediated by iron(III) sulfate/O2 has been developed. The reaction offered good yields and excellent regioselectivity and showed good functional group tolerance (31 examples). The method is important, as few reports with limited substrate scope are available for such excellent oxidative cleavage of conjugated dienes
已经开发了由硫酸铁(III)/ O 2介导的1-芳基丁二烯对肉桂醛的简单,有效和环境友好的区域选择性氧化裂解。该反应提供了良好的产率和优异的区域选择性,并显示出良好的官能团耐受性(31个实施例)。该方法很重要,因为很少有报道报道可对共轭二烯进行如此出色的氧化裂解的底物范围有限。
Aqueous Wittig reactions of semi-stabilized ylides. A straightforward synthesis of 1,3-dienes and 1,3,5-trienes
作者:James McNulty、Priyabrata Das
DOI:10.1016/j.tetlet.2009.07.133
日期:2009.10
A direct synthesis of 1,3-dienes and 1,3,5-trienes from the reaction of semi-stabilized ylides and a range of saturated and unsaturated aldehydes is reported in water as solvent, employing sodium hydroxide as base. The water-soluble phosphine oxide side product is removed simply by aqueous partitioning of the organic products.
yields and excellent regio-, enantio-, and Z/E-selectivities. The utility of this transformation was demonstrated by a broad range of styrenes and 1,3-dienes, facile product modification, and synthesis of bioactive compounds (R)-(-)-curcumene and (S)-(+)-ibuprofen. Mechanistic studies demonstrated the carboxylation of phenylethylcopper complexes with CO2 as one key step.
在此,我们报告了具有 1 个大气压的 CO2 的苯乙烯和 1,3-二烯的高度区域选择性和对映选择性铜催化还原羟甲基化。各种重要的手性高苄醇很容易从苯乙烯制备。此外,各种 1,3-二烯也以高产率和优异的区域选择性、对映选择性和 Z/E 选择性转化为手性高烯丙醇。广泛的苯乙烯和 1,3-二烯、简便的产品改性以及生物活性化合物 (R)-(-)-姜黄烯和 (S)-(+)-布洛芬的合成证明了这种转化的效用。机理研究表明,苯乙基铜配合物与 CO2 的羧化是一个关键步骤。
Radical-Mediated Heck-Type Alkylation: Stereoconvergent Synthesis of Functionalized Polyenes
作者:Hong Zhang、Xinxin Wu、Yunlong Wei、Chen Zhu
DOI:10.1021/acs.orglett.9b02838
日期:2019.9.20
The stereospecific synthesis of polyenes is of great synthetic value. Disclosed herein is a new, efficient, stereoconvergent approach for the synthesis of functionalized polyenes via a radical-mediated Heck-type alkylation. The easily accessed Z- and E-mixed alkenes are harnessed as starting material, leading to a unique stereoisomer of polyenes. In addition, the transformation features mild reaction