121045-01-0Relevant academic research and scientific papers
Ruthenium-catalysed synthesis of chiral exocyclic allylic alcoholsviachemoselective transfer hydrogenation of 2-arylidene cycloalkanones
Zhang, Kaili,Liu, Qixing,He, Renke,Chen, Danyi,Deng, Zhangshuang,Huang, Nianyu,Zhou, Haifeng
, p. 1628 - 1632 (2021/03/09)
An exclusive asymmetric reduction of C=O bonds of 2-arylidene four-, five-, six-, and seven-membered cycloalkanones has been studied systematically. The asymmetric transfer hydrogenation was performed using a robust and commercially available chiral diamine-derived ruthenium complex as a catalyst and HCOOH/Et3N as a hydrogen source under mild conditions, giving 51 examples of chiral exocyclic allylic alcohols in up to 96% yield and 99% ee. This method was also applicable to the gram-scale synthesis of the active intermediates of the anti-inflammatory loxoprofen and natural product (?)-goniomitine.
THE EFFECTS OF SUBSTITUENS AND SOLVENT POLARITY ON PHOTOCHEMICAL SIGMATROPIC SHIFTS. EXPERIMENTAL EVIDENCE IN FAVOUR OF THE OCCURRENCE OF SUDDEN POLARIZATION IN ACYCLIC ALKENES
Peijnenburg, W. J. G. M.,Buck, H. M.
, p. 4927 - 4940 (2007/10/02)
Furher experimental evidence regarding the occurence of sudden polarization in acyclic alkenes is presented.It is shown that the yield of formation of the product derived from an intramolecular photochemical -OH shift in the 1 is dependent only on the polarity of the solvent employed.This result could be well explained in terms of a stabilization of the zwitterionic intermediate formed upon irradiation of 1 by reorientation polarization of the dipole solvent molecules.Besides this, it was found that replacement of the alkyl group at the terminal carbon atom of the C3-C9 exocyclic double bond in 1 by a phenyl substituent led to the occurence of a photochemical -H shift.This directive effect of the substituents at the exocyclic double bond could be well explained on the basis of the sudden polarization model.
