The first example of rhodium(I)-catalyzed regio and stereoselective chloroesterification of alkynes with chloroformate esters
The first example of rhodium(I)-catalyzed regio and stereoselective chloroesterification of alkynes with chloroformate esters
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DOI：
10.1021/ja9822299
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发表时间：
1998-12-02
影响因子：
15
通讯作者：
Tanaka, M
中科院分区：
文献类型：
--
作者：
Hua, RM;Shimada, S;Tanaka, M
炔与一氧化碳和醇或与甲酸酯的加氢酯化反应是一个具有重要实际意义的过程。然而，相应的氯酯化反应，提供了一步合成β-氯- r， β-不饱和酯具有很大的合成潜力3，从未报道过。近年来，我们对过渡金属配合物催化的EE ‘键（E, E ’杂原子或官能团）与炔烃的加成反应很感兴趣，以期一步合成双官能团烯烃。在这一领域的研究导致了炔与氯甲酸酯(E) Cl, E ') COOR的高效氯酯化反应的发现。在一个有代表性的实验中，将1-己炔1 （0.2 mmol）、氯甲酸甲酯2a （0.6 mmol）和催化量的RhCl (CO)(PPh3) 2 （0.002 mmol）的混合物溶解在甲苯（0.5 mL）中，在110℃下加热10 h。GC和GC- ms分析表明，甲基(Z)-3-氯-2-庚酸3a及其区域异构体4a的形成比例为97:3 (eq 1
Hydroesterification of alkynes with carbon monoxide and alcohols1 or with formate esters2 is a process of great practical importance. However, the corresponding chloroesterification reaction, which provides a one-step synthesis of β-chloro-R, β-unsaturated esters with much synthetic potential, 3 has never been reported. In recent years we have been interested in transition metal complex-catalyzed addition reactions of EE′ bonds (E, E′) heteroatom or functional group) to alkynes in order to synthesize doubly functionalized alkenes in a single step. 4 Research in this area has led to the discovery of the efficient chloroesterification of alkynes with chloroformates (E) Cl, E′) COOR).In a representative experiment, a mixture of 1-hexyne 1 (0.2 mmol), methyl chloroformate 2a (0.6 mmol), and a catalytic amount of RhCl (CO)(PPh3) 2 (0.002 mmol) dissolved in toluene (0.5 mL) was heated at 110 C for 10 h. GC and GC-MS analyses suggested the formation of methyl (Z)-3-chloro-2-heptenoate 3a and its regioisomer 4a in a ratio of 97: 3 (eq 1; R