Phenanthroline and tert-butoxide have been established as powerful radical initiators in reactions such as the S(RN)1-type coupling reactions due to the cooperation of large heteroarenes and a special feature of tert-butoxide. The first phenanthroline-tert-butoxide-catalyzed transition-metal-free allylic isomerization is described. The resulting ketones are key intermediates for indenes. The control experiments rule out the base-promoted allylic anion pathway. The radical pathway is supported by experimental evidence that includes kinetic study, kinetic isotope effect, isotope-labeling experiments, trapping experiments, and EPR experiments.
A Positional Scanning Approach to the Discovery of Dipeptide-Based Catalysts for the Enantioselective Addition of Vinylzinc Reagents to Aldehydes
作者:Christopher M. Sprout、Meaghan L. Richmond、Christopher T. Seto
DOI:10.1021/jo051342w
日期:2005.9.1
crude form as catalysts for the asymmetric addition of vinylzinc reagents to aldehydes to give chiralallylicalcohols. Three sites of diversity on the ligands were optimized using a positional scanning approach. The optimized structure from the library, ligand 54, was found to catalyze the formation of 10 different (E)-allylicalcohols with enantioselectivities ranging from 90% to 95% ee. This ligand was
Cyclopropyl Grignard reagents react with carbonyl compounds in the presence of diethyl phosphite to give homoallylicbromides. The reaction is effectively carried out under mild conditions in a one-pot fashion with moderate to good yields.
1,1,1,3,3,3-Hexafluoro-2-propanol (HFIP)-Assisted Catalyst-Free Sulfonation of Allylic Alcohols with Sulfinyl Amides
作者:Zhen Luo、Zheng-Qiang Liu、Ting-Ting Yang、Xin Zhuang、Chuan-Ming Hong、Fei-Fei Zou、Zhi-Yong Xue、Qing-Hua Li、Tang-Lin Liu
DOI:10.1021/acs.orglett.1c04206
日期:2022.1.21
A highly regioselective and catalyst-free sulfonation of allylic alcohols with sulfinyl amides has been realized. Such a mix-and-go procedure provides a convenient approach to synthetically various allylic sulfones under mild reaction conditions. Furthermore, this novel reaction shows ample substrate scope and outstanding functional group tolerance and could also be scaled-up. Meanwhile, it is the
of cyclopropanemethanols with pyridinium poly(hydrogenfluoride) in the presence of diisopropylamine and KHF2 gave selectively homoallylic fluorides or fluorocyclobutanes according to the mode of substitution of the starting cyclopropanemethanols. Cyclopropanemethanols with no substitution at 1-position of the cyclopropane ring gave homoallylic fluorides in a stereoselective manner. While, 1-methyl
Treatment of cyclopropylmethanols with pyridinium poly(hydrogen fluoride) in chlorobenzene-diisopropylamine in the presence of KHF2 gave selectively homoallylic fluorides.