Catalytic Enantioselective Ring-Closing Metathesis by a Chiral Biphen-Mo Complex was written by Alexander, John B.;La, Daniel S.;Cefalo, Dustin R.;Hoveyda, Amir H.;Schrock, Richard R.. And the article was included in Journal of the American Chemical Society in 1998.SDS of cas: 205927-03-3 This article mentions the following:
The enantioselective synthesis of chiral Mo-alkylidene I is reported. This nonracemic transition metal complex bears 5,5′,6,6′-tetramethyl-3,3′-di-tert-butyl-1,1′-biphenyl-2,2′-diol as the chiral ligand, which is resolved by recrystallization of the derived phosphoric acid with optically pure cinchonidine. The catalyst structure is characterized by x-ray crystallog., as well as routine spectroscopic methods. I effects enantioselective ring-closing metathesis efficiently and with excellent selectivity. Depending on the substitution pattern of the reacting alkenes, either the diene substrate or the cycloalkenyl product can be obtained in >92% ee, corresponding to krel of up to 58. In the experiment, the researchers used many compounds, for example, (S)-3,3′-Di-tert-butyl-5,5′,6,6′-tetramethylbiphenyl-2,2′-diol (cas: 205927-03-3SDS of cas: 205927-03-3).
(S)-3,3′-Di-tert-butyl-5,5′,6,6′-tetramethylbiphenyl-2,2′-diol (cas: 205927-03-3) belongs to copper catalysts. Copper has continued to be one of the most utilized and important transition metal catalysts in synthetic organic chemistry. It is clear from the impact copper catalysis has had on organic synthesis that copper should be considered a first line catalyst for many organic reactions.SDS of cas: 205927-03-3
Referemce:
Copper catalysis in organic synthesis – NCBI,
Special Issue “Fundamentals and Applications of Copper-Based Catalysts”