Copper-Catalyzed Cross-Coupling of Alkyl and Phosphorus Radicals for C(sp<sup>3</sup>)–P Bond Formation
作者:Cheng-Kun Li、Ze-Kun Tao、Adedamola Shoberu、Wei Zhang、Jian-Ping Zou
DOI:10.1021/acs.orglett.2c02454
日期:2022.8.19
A CuI-catalyzed cross-coupling of alkyl- and phosphorus-centered radicals for C(sp3)–P bondformation is introduced. Diacyl peroxides, generated in situ from aliphatic acids and H2O2, serve as a source for alkyl radicals and also an initiator for the generation of phosphorus radicals from H–P(O) compounds.
介绍了一种 Cu I催化的以烷基和磷为中心的自由基的交叉偶联,以形成 C(sp 3 )-P 键。由脂肪酸和 H 2 O 2原位生成的二酰基过氧化物可作为烷基自由基的来源,也是从 H-P(O) 化合物生成磷自由基的引发剂。
Opposite Stereochemical Effects Exerted by CeCl3 and TiCl4 on the Lewis Acid Mediated Reduction of α-Alkyl-β-ketophosphine Oxides with Metallic Hydrides: A Highly Stereoselective Protocol for the Synthesis of syn and anti α-alkyl-β-Hydroxyphosphine Oxides
AbstractA general, highly efficient methodology for obtaining both syn and anti β‐hydroxyphosphine oxides by reduction of the corresponding β‐ketophosphine oxides is described. The nature of the Lewis acid was found to be pivotal in determining the outcome of these reactions. Strongly chelating TiCl4 led to the anti isomer in high diastereoisomeric excess in noncoordinating solvents (CH2Cl2) at ‐78°C with BH3/py as reducing agent, while nonchelating CeCl3 gave a high excess of the syn isomer in coordinating solvents (THF) at the same temperature with LiBH4 as reducing agent. In the latter case, CeCl3 is essential in achieving high yields and stereoselectivity, since it allows the reaction to be performed at low temperatures. Otherwise, higher temperatures (0°C) are required, which lower both yields and selectivities. Moreover, each step of the protocol for the synthesis of stereodefined disubstituted olefins from alkylphosphine oxides (Warren's modification of the Horner procedure) has been optimized, and the optimized procedure has been applied to the synthesis of muscalure, the pheromone of the domestic fly.
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