Selective organic synthesis through generation and reactivity control of hyper‐coordinate metal species

This paper is a review of my 40 years of research at Kyoto, Sagamihara, and Yokohama, all based on the generation of hyper‐coordinate metal species such as ate complexes and pentacoordinate silicates. The topics are: (i) carbenoid reagents for carbon–carbon bond‐forming reactions, (ii) nucleophilic substitution at acetal carbons using aluminate reagents, (iii) preparation of magnesium enolates and its reaction with nitriles, (iv) Cr(II) reagents for reduction of organic halides and highly selective carbon–carbon bond formation, (v) organic synthesis with organosilion reagents/fluoride ions, (vi) cross‐coupling reaction of organosilicon compounds, and (vii) silicon‐based conjugate addition to α,β‐unsaturated carbonyl acceptors. © 2008 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 8: 337–350; 2008: Published online in Wiley InterScience ( www.interscience.wiley.com ) DOI 10.1002/tcr.20162     

Cobalt-Catalyzed Asymmetric Aza-Nozaki–Hiyama–Kishi (NHK) Reaction of α-Imino Esters with Alkenyl Halides

Chromium-catalyzed enantioselective Nozaki–Hiyama–Kishi (NHK) reaction represents one of the most powerful approaches for the formation of chiral carbon-heteroatom bond. However, the construction of sterically encumbered tetrasubstituted stereocenter through NHK reaction still posts a significant challenge. Herein, we disclose a cobalt-catalyzed aza-NHK reaction of ketimine with alkenyl halide to provide a convenient synthetic approach for the manufacture of enantioenriched tetrasubstituted α-vinylic amino acid. This protocol exhibits excellent functional group tolerance with excellent 99 % ee in most cases. Additionally, this asymmetric reductive method is also applicable to the aldimine to access the trisubstituted stereogenic centers.     

紫草素类似物全合成研究

以1,4-二氢基萘醌为原料,经过甲基化、甲酰化、NHK(Nozaki-Hiyama-Kishi)反应、硝酸铈铵(cAN)和AgO/HNO3氧化脱甲氧基等5步反应,完成了一条紫草素类似物新的合成路线.该路线能够简便、快速地合成紫草素类似物.