A study of the double bond reactivity in Δ3-cyclohexene derivatives with one polar substituent in the side chain and Me substituents in the ring has shown that the preferred conformation for these compounds, indepenent of their stereochemistry, has the polar group axial, giving rise to supra-annular interaction. Such interaction decreases the nucleophilicity of the ring double bond. A similar study
Synthesis of <i>gem</i>-Difluoroalkenes via Nickel-Catalyzed Reductive C–F and C–O Bond Cleavage
作者:Zhiyang Lin、Yun Lan、Chuan Wang
DOI:10.1021/acscatal.8b04348
日期:2019.1.4
By merging C–O and C–F bondcleavage in cross-electrophile coupling, we developed a method for efficient synthesis of gem-difluoroalkenes with an alkoxy-substituent on the homoallylic position using easily accessible acetals as coupling partners with α-trifluoromethyl alkenes. Remarkably, this Ni-catalyzed allylic defluorinative cross-coupling reaction demonstrates high tolerance of a wide range of
A mild route to α‐alkoxyacetylenes mediated by lewis acids and synthetic routes to 10‐, 11‐, and 12‐membered ring enediyne carbocycles
作者:Bogdan M. Comanita、Matthew A. Heuft、Tanya Rietveld、Alex G. Fallis
DOI:10.1560/7j4f-d8bg-3fqr-e3td
日期:2000.12
The condensation of silyl substituted acetylenes with dimethoxy acetals via a modified “Mukaiyama-type reaction” to afford α-alkoxyacetylenes is described. These propargylic ethers 17–21 were synthesized from the reaction of aluminum or zinc acetylides with acetals mediated by Lewis acids. In appropriate cases, when a second acetal was present in the initial acyclic product (24), a subsequent intramolecular
A hair relaxer includes at least one specific mercapto compound such as 2-methoxyethyl 3-mercaptopropionate, 2-mercapto-4-butanolide and 2-mercapto-4-butyrolactam. The hair relaxer can achieve an excellent effect of shaping and relaxing hair over a wide range of pH values from weak acidity to weak alkalinity. In particular, the hair relaxer displays a more superior hair shaping and relaxing performance in a weakly acidic to neutral pH range. Consequently, the hair relaxer can drastically reduce the damage to the hair and skin and can reliably perform straightening, uncurling, curling and other hair processing.