956-86-5Relevant academic research and scientific papers
Facile pinacol coupling of aliphatic ketones by Brook rearrangement in the presence of samarium species
Wang, Xincan,Xie, Guanqun,Zhao, Yanfei,Zheng, Ke,Fang, Yanxiong,Wang, Xiaoxia
supporting information, (2021/04/27)
Herein we report a practical pinacol coupling reaction, in which ketones (aldehydes) react smoothly with Sm and TMSBr to afford the diol products with Sm(II) or (III) siliyl species generated in situ. This reported method affords poor yields for aromatic ketone substrates and good yields for aliphatic ketones. Therefore, it distinguishes from most reductive coupling approaches that are more effective for aromatic carbonyl compounds and provides a facile and robust approach for the pinacol coupling of aliphatic ketones. Mechanistic studies also indicated the pinacolization probably proceeded via an anionic instead of radical coupling pathway involving the Brook rearrangement in the presence of samarium (II or III) silyl species.
Samarium diiodide-catalyzed diastereoselective pinacol couplings
Aspinall, Helen C.,Greeves, Nicholas,Valla, Carine
, p. 1919 - 1922 (2007/10/03)
(Chemical Equation Presented) A complex of samarium diiodide (Sml 2) with tetraglyme catalyzes the intermolecular pinacol coupling of aromatic or aliphatic aldehydes at loadings of 10 mol % in the presence of Me2SiCl2 and Mg. Diastereoselectivity of up to 95/5 (±/meso) has been achieved for aliphatic aldehydes and up to 19/81 (±/meso) for aromatic aldehydes. De values of up to 99% have been achieved in intramolecular pinacol coupling reactions using the Sml 2/tetraglyme/Mg/Me2SiCl2 catalytic system.
Efficient method for the preparation of pinacols derived from aromatic and aliphatic ketones by using low-valent titanium reagents in dichloromethane-pivalonitrile
Kagayama,Igarashi,Mukaiyama
, p. 657 - 665 (2007/10/03)
The reductive coupling reaction of aldehydes and ketones, including unsymmetrical aliphatic ketones, proceeded smoothly to give the corresponding pinacols in good to high yields under mild conditions by using combination of titanium(II) chloride and zinc or titanium(IV) chloride and zinc in dichloromethane-pivalonitrile. Meso-selective formation of the coupling products was observed in the cases of some aliphatic ketones. The diastereoselectivities of coupling products depend on both difference of bulkiness of 2-, and 2'-substituents of carbonyl group of the reactant, and overall steric effect around the carbonyl groups.
