Molybdenum-Mediated Vinylidene Rearrangement of Internal Acyalkynes and Sulfonylalkynes
Molybdenum-Mediated Vinylidene Rearrangement of Internal Acyalkynes and Sulfonylalkynes
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钼介导的内部酰基炔和磺酰基炔的亚乙烯基重排
DOI：
10.1021/acs.organomet.9b00019
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发表时间：
2019
期刊：
影响因子：
2.8
通讯作者：
Y. Ishii
中科院分区：
文献类型：
--
作者：
T. Kuwabara;K. Sakajiri;Y. Oyama;S. Kodama;Y. Ishii
介绍了内酰基炔和磺酰基炔在d 6钼中心的亚乙烯基重排反应。[（η7-C7 H7）MoBr（dppe）]与不同的酰基炔R-C C-COR′在NaBArF 4存在下反应，得到相应的亚乙烯基配合物[（η7-C7 H7）Mo[C C-COR ′]（dppe）][BArF 4]，其在室温下以两种旋转异构体的混合物存在，以Mo Cα键为例，NMR研究表明.这提供了内部炔在Mo中心的亚乙烯基重排的第一个例子。X-射线衍射研究表明，亚乙烯基配体：C_2CR（COR′）的配位几乎垂直于C_7H_7平面。A13 C标记实验揭示了酰基的选择性迁移，这与亲核1，2-迁移机制一致。以磺酰基炔R-C_2C-SO_2 R ′为底物，根据R基团的不同，分离出三种类型的产物：η2-炔、亚乙烯基和非预期的η2-膦酰基炔络合物.η2-膦酰基炔络合物被认为是通过膦对磺酰基的亲核取代产生的。
Vinylidene rearrangement of internal acylalkynes and sulfonylalkynes at a d6molybdenum center is presented. Treatment of [(η7-C7H7)MoBr(dppe)] with various acylalkynes R–C≡C–COR′ in the presence of NaBArF4afforded the corresponding vinylidene complexes [(η7-C7H7)Mo[═C═CR(COR′)](dppe)][BArF4], which exist as mixtures of two rotamers, with respect to the Mo═Cαbond at room temperature, as evidenced by NMR studies. This provides the first example of vinylidene rearrangement of internal alkynes at a Mo center. X-ray diffraction studies revealed that the vinylidene ligand :C═CR(COR′) coordinates almost perpendicularly toward the C7H7plane. A13C-labeling experiment unveiled selective migration of the acyl group, which is in agreement with a nucleophilic 1,2-migration mechanism. When sulfonylakynes R–C≡C–SO2R′ were used as substrates, three types of products—η2-alkyne, vinylidene, and unexpected η2-phosphonioalkyne complexes—have been isolated, depending on the R group. The η2-phosphonioalkyne complex is considered to be generated through nucleophilic substitution of the sulfonyl group by a phosphine.