Ogasawara, Masamichi; Watanabe, Susumu; Nakajima, Kiyohiko; Takahashi, Tamotsu published an article on February 24 ,2010. The article was titled 《Enantioselective synthesis of planar-chiral phosphaferrocenes by molybdenum-catalyzed asymmetric interannular ring-closing metathesis》, and you may find the article in Journal of the American Chemical Society.Safety of (R)-3,3′-Di-tert-butyl-5,5′,6,6′-tetramethylbiphenyl-2,2′-diol The information in the text is summarized as follows:
Planar-chiral nonracemic phosphaferrocenophanes I [2a-f; a, R = H, R1 = H, X-X = (CH2)4, Z = CH2; b, R = Me, R1 = H, X-X = (CH2)4, Z = CH2; c, R = Me, R1 = Me, X-X = (CH2)4, Z = CH2; d, R = Me, R1 = H, X-X = CH2OCH2, Z = CH2; e, R = Me, R1 = H, X-X = (CH2)5, Z = CH2; f, R = Me, R1 = H, X-X = (CH2)4, Z = CH2CH2] were prepared by asym. ring-closing metathesis of the corresponding precursors, [[η5-3,4-X2-2,5-(CH2:CRCH2)2C5](η5-C5R14ZCH:CH2)Fe] (1a-f), catalyzed by chiral BINOL molybdenum(IV) carbene-imido complexes [(Ln)Mo:CHCMe2Ph(DippN)] [Mo-1-Mo-3, L1 = (R)-3,3′-tBu2-1,1′-octahydrobinaphthalene-2,2′-diolato, L2 = (R)-3,3′-[3,5-(CF3)2C6H3]2-1,1′-binaphthalene-2,2′-diolato, L3 = (R)-3,3′-[2,5-(CF3)2C6H3]2-1,1′-binaphthalene-2,2′-diolato]. Enantioselective synthesis of planar-chiral phosphaferrocenes was realized for the first time by molybdenum-catalyzed asym. ring-closing metathesis (ARCM) in up to 99% ee, which is the first application of ARCM to induction of chirality in mols. devoid of stereogenic centers. After reading the article, we found that the author used (R)-3,3′-Di-tert-butyl-5,5′,6,6′-tetramethylbiphenyl-2,2′-diol(cas: 329735-68-4Safety of (R)-3,3′-Di-tert-butyl-5,5′,6,6′-tetramethylbiphenyl-2,2′-diol)
(R)-3,3′-Di-tert-butyl-5,5′,6,6′-tetramethylbiphenyl-2,2′-diol(cas: 329735-68-4) belongs to phenols. Phenols are more acidic than typical alcohols.Safety of (R)-3,3′-Di-tert-butyl-5,5′,6,6′-tetramethylbiphenyl-2,2′-diol The acidity of the hydroxyl group in phenols is commonly intermediate between that of aliphatic alcohols and carboxylic acids (their pKa is usually between 10 and 12).
Referemce:
Alcohol – Wikipedia,
Alcohols – Chemistry LibreTexts