Development of an axially chiral sp3P/sp3NH/sp2N-combined linear tridentate ligand—fac-selective formation of Ru(II) complexes and application to ketone hydrogenation
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- 作者：Tomoya Yamamura ; Satoshi Nakane ; Yuko Nomura ; Shinji Tanaka ; Masato Kitamura ; kitamura@os.rcms.nagoya-u.ac.jp" class="auth_mail" title="E-mail the corresponding author
- 关键词：Chiral ligand ; Tridentate ; fac-Ru complex ; Catalysis ; Hydrogenation
- 刊名：Tetrahedron
- 出版年：2016
- 出版时间：30 June 2016
- 年：2016
- 卷：72
- 期：26
- 页码：3781-3789
- 全文大小：2229 K
文摘
A newly developed chiral linear tridentate ligand, R-PN(H)N (R=H or Ph), possesses Ph2P and PyCH2NH groups at C(2) and C(2′) positions of the 1,1′-binaphthyl skeleton without or with a C(3)-Ph substituent. The steric effect of C(3)-Ph and the electronic effect of the DMSO co-ligand realize the facial selective generation of fac-RuCl2(Ph-PN(H)N)(dmso) and fac-[Ru(H-PN(H)N)(dmso)3](BF4)2, respectively. Both an H–Ru⋯sp3N–H reaction site responsible for the donor–acceptor bifunctional catalyst (DACat) and a fence/plane chiral context were constructed by means of the following advantageous points: i) the sp3P, sp3N, and sp2N ligating atoms have different electronic properties; ii) DMSO trans to sp3N strongly coordinates to Ru and is fixed by a PyC(6)H⋯O
S hydrogen bond; and iii) the single NH function simplifies the DACat reaction site. The synergistic effect has led to success in the asymmetric hydrogenation of sterically demanding ketones. Structural characteristics of first-row transition metal complexes of R-PN(H)N have been also investigated.
S hydrogen bond; and iii) the single NH function simplifies the DACat reaction site. The synergistic effect has led to success in the asymmetric hydrogenation of sterically demanding ketones. Structural characteristics of first-row transition metal complexes of R-PN(H)N have been also investigated.