We describe a cerium‐catalyzed aerobic oxidative ringexpansion for the expedient construction of synthetically challenging macrolactones under visible‐light conditions. Cyanoanthracene has been employed as co‐catalyst to accelerate the turnover of the cerium cycle leading to a fast conversion within 20 min of irradiation. Taking advantage of the high efficiency and operationally simple conditions
Chiral diselenide ligands for the asymmetric copper-catalyzed conjugate addition of Grignard reagents to enones
作者:Antonio L Braga、Sandra J.N Silva、Diogo S Lüdtke、Roberta L Drekener、Claudio C Silveira、Joao B.T Rocha、Ludger A Wessjohann
DOI:10.1016/s0040-4039(02)01713-6
日期:2002.10
The copper-catalyzed conjugate addition of Grignard reagents to enones in the presence of chiral diselenide oxazoline ligands has been studied and found to provide good yields and useful levels of asymmetric induction.
Chiral mercaptoaryl-oxazolines as ligands in asymmetric catalysis: Enantioselective Cu-catalyzed 1,4-addition of Grignard reagents to α,β-unsaturated ketones
作者:Qi-Lin Zhou、Andreas Pfaltz
DOI:10.1016/s0040-4039(00)61549-6
日期:1993.11
Copper(I) thiolate complexes derived from chiral mercaptophenyl-oxazolines 3 have been studied as enantioselective catalysts for the 1,4-addition of Grignard reagents to α,β-unsaturated ketones. For cyclic enones enantioselectivities increase in the sequence cyclopentenone (16–37% ee) < cyclohexenone (60–72 % ee) < cycloheptenone (83–87% ee).
Soft Enolization of 3-Substituted Cycloalkanones Exhibits Significantly Improved Regiocontrol vs Hard Enolization Conditions
作者:Natalie C. Dwulet、Vincenzo Ramella、Christopher D. Vanderwal
DOI:10.1021/acs.orglett.1c03844
日期:2021.12.17
markedly better than the typically applied hard enolization protocols for regioselective enoxysilane formation from unsymmetrical 3-substituted cycloalkanones. Five-, six-, and seven-membered cycloalkanones each with 3-methyl, 3-isopropyl, or 3-phenyl substituents were investigated, and in all but one case, regioselectivities were ≥11:1 for enolization away from the substituent. These results are complementary
Electroreduction of cycloheptatriene or substituted cycloheptatrienes in the presence of an alkyl halide was found to be a unique and effective method for introducing regioselectively an alkyl group into seven-membered ring system and it was applied to a newsynthesis of β-thujaplicin (hinokitiol).