63992-30-3

Upstream product

• 585-34-2 3-tert-butylphenyol 
• 150-76-5 4-methoxy-phenol 
• 20942-70-5 2-iodo-5-(1,1-dimethylethyl)phenol 
• 1245928-51-1 (4-(tert-butyl)-2-methoxyphenyl)boronic acid 
• 934180-29-7 4-(tert-butyl)-1-iodo-2-methoxybenzene 
• 685108-66-1 2,2'-dimethoxy-4,4'-bis(tert-butyl)biphenyl 
• 1625-91-8 4,4'-di-tert-butylbiphenyl 

Downstream Products

• 1245928-54-4 C₄₄H₄₄P₂ 
• 1245928-53-3 C₄₄H₄₄O₂P₂ 
• 32750-01-9 6,6'-dimethyl-2,2'-biphenyldiol 

Relevant academic research and scientific papers

Stable axial chirality in metal complexes bearing 4,4′-substituted BIPHEPs: Application to catalytic asymmetric carbon-carbon bond-forming reactions

Not only electronic but also steric effects of 4,4′-substituents in BIPHEP derivatives and metal (Pd, Pt, and Au) complexes are shown to influence the stability of the biphenyl single bond rotation. While electron-donating or sterically demanding substituents on the 4,4′-positions destabilize the axial chirality of BIPHEP derivatives, electron-withdrawing or sterically less demanding ones on the 4,4′-positions stabilize the axis chirality. Particularly, the axial chirality of palladium dichloride complexes bearing BIPHEP with t-Bu and CF3 substituents on the 4,4′-positions is most labile and stable, respectively (ΔG≠ = 29.22 and 30.49 kcal mol-1 at 300 K; t1/2 = 7 and 56 years at 300 K). These enantiopure dicationic BIPHEPPd complexes can be employed for catalytic enantioselective arylation, alkenylation, and ene reactions to give the corresponding products in good-to-excellent yields and enantioselectivities. Significantly, in the carbonyl-ene reaction of trifluoropyruvate with isobutene, the turnover frequency (TOF) reached 58200 h-1. The remarkable effects of 4,4′-substituents in BIPHEP derivatives can be employed as a guiding principle in the design of versatile and efficient ligands.

The superbase-mediated pairwise substitution of the 2,2′- and 6,6′-positions in a biphenyl derivative

The superbasic mixture of butyllithium and potassium tertbutoxide is powerful enough to enable the double proton abstraction from one ortho and one ortho′ position of 4,4′-di-tert-butylbiphenyl. In this way, a series of functionalized derivatives becomes readily accessible, among them 4,4′-di-tert-butylbiphenyldiyl-2,2′-dicarboxylic acid (2a) and 4,4′-ditert-butylbiphenyl-2,2′-diol (2d). The latter compound can be subjected again to a superbase-promoted double metalation, thus giving rise to 2,2′,6,6′-tetrasubstituted biphenyl derivatives. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.