938058-85-6Relevant articles and documents
Efficient synthesis of 2-methyl derivatives of 1,1′-bi(2-naphthol) and 1,1′-bi(2-phenols)
Solinas, Maurizio,Meadows, Rebecca E.,Wilson, Claire,Blake, Alexander J.,Woodward, Simon
, p. 1613 - 1623 (2008/02/06)
Reaction of 1,1′-binaphthol and structurally related 1,1′-biphenols with sulfonylating reagents [RSO2Cl; R = 4-Tol, Ph] leads to clean, ultraselective monoderivatisation, shown crystallographically in one case (2-OH-2′-OTs-1,1′-binaphthyl). Reaction of the remaining 2-hydroxy function with either Tf2O or NfF [Nf = nonaflate, CF3(CF2)3SO2-] affords the protected/activated cores (2-R1O-2′-R 2O-1,1′-biaryl) [R1,R2 pairs = Tf,Ts (X-ray); Tf,SO2Ph; Nf,Ts (on 1,1′-binaphthyl core); Tf,Ts; Nf,Ts (on 1,1′-biphenyl core); Tf,Ts; Nf,Ts (on 3,3′,5,5′- tetramethyl-1,1′-biphenyl core)]. Reaction of the Tf,Ts species with either MeMgBr/NiCl2(dppe) (for the 1,1′-binaphthyl) or (AlMe3)2(DABCO)/Pd2(dba)3 (for the 1,1′-biphenyl) affords 2-OH-2′-Me-1,1′-biaryl units on subsequent hydrolysis (crystallographically characterised in the binaphthyl case). The latter methyl/hydroxy compounds are doubly deprotonated by either nBuLi/TMEDA or nBuLi/tBuOK to afford dianions that react cleanly with Cl 2SiPh2 (two X-ray structures). The equivalent reaction of the 2-OH-2′-Me-1,1′-binaphthyl with Ph(O)Cl2 is less clean due to the absence of a strong Thorpe-Ingold effect. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.
