Copper-Catalyzed Stereospecific C–S Coupling Reaction of Enantioenriched Tertiary Benzylic Amines via in Situ Activation with Methyl Triflate
作者:Wenlong Jiang、Nutao Li、Lihong Zhou、Qingle Zeng
DOI:10.1021/acscatal.8b03032
日期:2018.11.2
1-(thiophen-2-yl)ethanamine), and aminoacid esters containing a benzylamine moiety, are highly efficient substrates, and their chirality is efficiently transferred to the products (94–99% ee). The absolute configurations of the products are predictable and follow the pattern of SN2-type substitutions; an inversion of the absolute configuration of the tertiary amines occurs during the C–S coupling reaction. Not only
A new protocol was developed to synthesize (enantioenriched) thioethers and selenoethersfrom (chiral) benzylic trimethylammonium salts and di(hetero)aryl disulfides or diselenides. These syntheses were promoted by the presence of weak base and did not require the use of any transition metal, and resulted in the target products with good to excellent yields (72–94%). Using quaternary ammonium salts
Cu2O-catalyzed C–S bond cross coupling of alkane-/arene-sulfinates and (enantioenriched) benzylic quaternaryammoniumsalts has been developed. The product benzylic sulfones were obtained in good to high yields (75–96%). Chiral arylmethyl sulfones with high enantiomeric excess (90–94% ee) were also synthesized in the presence of Cu2O and 1,1′-bis-(diphenylphosphino)ferrocene (dppf).
bond and the conformation of the Pd–phosphine fragment can be found and NMR data permit the assignment of the absoluteconfiguration of the phosphine in [PdCl(C10H6CHMeNMe2)(PBnCyPh)]. Several molecular mechanics geometry optimizations were performed using the MMFF94 force field to estimate the height of the energy barrier corresponding to the rotation of the phosphine ligands around the PdP bond. These
报道了旋光络合物[PdCl(C 10 H 6 CHMeNMe 2)L](L = PPh 3,PBn 2 Ph,PHBnPh和PBnCyPh)的合成和仲膦PHBnPh的拆分。这些单核化合物的NMR数据研究表明,在某些配合物中,绕Pd = P键的旋转受到限制。可以发现与PdC键相邻的芳族质子的δ值与Pd-膦片段的构象之间的关系,并且NMR数据可以确定[PdCl(C 10 H 6)中膦的绝对构型化学2)(PBnCyPh)]。使用MMFF94力场进行了一些分子力学几何优化,以估计与PdP键周围的膦配体旋转对应的能垒高度。这些计算表明,如果该膦含有至少一个苄基,则绕Pd = P键的旋转受到限制,并且与通过一维和二维NMR在溶液中获得的结果一致。
Challenges in cyclometalation: steric effects leading to competing pathways and η<sup>1</sup>,η<sup>2</sup>-cyclometalated iridium(<scp>iii</scp>) complexes
作者:Houguang Jeremy Chen、Ronald Hong Xiang Teo、Jonathan Wong、Yongxin Li、Sumod A. Pullarkat、Pak-Hing Leung
DOI:10.1039/c8dt02639d
日期:——
in the presence of a base afforded an assortment of products ranging from organic molecules to coordinated systems and cyclometalated complexes. The transformation affirmed the postulation where stericeffects within the coordination sphere favor a β-hydride elimination-like decomposition pathway, competing alongside ortho-metalation, thus leading to iminium intermediates. The same procedure also generated