Phosphonites Based on the Paracyclophane Backbone: New Ligands for Highly Selective Rhodium-Catalyzed Asymmetric Hydrogenation was written by Zanotti-Gerosa, Antonio;Malan, Christophe;Herzberg, Daniela. And the article was included in Organic Letters in 2001.Safety of (S)-3,3′-Di-tert-butyl-5,5′,6,6′-tetramethylbiphenyl-2,2′-diol This article mentions the following:
The synthesis of new phosphonites with a chiral paracyclophane backbone is described. The Rh complexes derived from the phosphonites (e.g. I) bearing biphenoxy and binaphthoxy substituents are highly active and highly selective catalysts for the asym. hydrogenation of dehydroamino acids and esters. For example, >99% N-acetylalanine Me ester with 99 %ee was obtained in 1/2 h using the Rh complex of I. 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: 205927-03-3Safety of (S)-3,3′-Di-tert-butyl-5,5′,6,6′-tetramethylbiphenyl-2,2′-diol).
(S)-3,3′-Di-tert-butyl-5,5′,6,6′-tetramethylbiphenyl-2,2′-diol (cas: 205927-03-3) belongs to copper catalysts. Copper catalyst has received great attention owing to the low toxicity and low cost. Copper nanoparticles can also catalyze the coupling reaction of nitrogen-containing nucleophiles, phenols, thiols, xanthogenates, selenium ruthenium nucleophiles and the like.Safety of (S)-3,3′-Di-tert-butyl-5,5′,6,6′-tetramethylbiphenyl-2,2′-diol
Referemce:
Copper catalysis in organic synthesis – NCBI,
Special Issue “Fundamentals and Applications of Copper-Based Catalysts”