Alkylpolyphenyls. I. 4'-Alkyl-m-terphenyls¹

Synthesis of Magnaldehydes B and E and Dictyobiphenyl B by Microwave‐Promoted Cross‐Coupling of Boronophenols

“…By starting from commercially available p-hydroxybenzaldehyde (5), we prepared monobrominated product 6 by following our previously published procedure (Scheme 1). [37] In the next step, the o,pЈ-biphenol moiety was constructed by a Suzuki-Miyaura coupling reaction. These cross-coupling reactions generally require base, which is believed to accelerate the transmetalation step by enhancing the nucleophilicity of the boronic acid through the formation of the corresponding boronate (boronate mechanism) or the substitution of a Pd-bonded halide by an alkoxide or hydroxide (oxo-Pd mechanism).…”

“…3-Bromo-4-hydroxybenzaldehyde (6) was synthesized according to a literature procedure. [37] The Pd/C that was used for all experiments was purchased from Sigma-Aldrich (product number 205699, 9.8-10.2 % Pd on dry support, reduced, average particle size of the carbon is 15 μm, surface area of the carbon support is 750-1000 m 2 g -1 ). [45]…”

“…[36] Previously, we discovered that all of the regioisomeric biphenols can be synthesized by protecting-group-free Suzuki-Miyaura coupling reactions of boronophenols and halophenols with water as the solvent and commercial Pd/ C as the precatalyst. [37,38] However, the success of the crosscoupling reactions crucially depends on the appropriate choice of additive and heating conditions to produce the desired positional isomer. On the basis of these experiences, we investigated the syntheses of magnaldehydes B (3a) and E (4a) along with their 4Ј-methyl ethers 3b and 4b, respectively, by employing a common intermediate.…”

Ultrasound-promoted chiral fluorescent organogel

“…13 (S)-3,3 0 -Bis((2,2 0 -bipyridin)-5-yl)-2,2 0 -dimethoxymethoxy-1,1 0binaphthyl (S)-7. (S)-7 is prepared from 5-bromo-2,2 0 -bipyridine 19 and 2,2 0 -dimethoxymethoxy-1,1 0 -binaphthyl-3,3 5-(4-(3-Ethoxynaphthalen-2-yl)-phenyl)-2,2 0 -bipyridine 8. 8 is synthesised according to the procedures described in Fig.…”

Rhodium(III)‐Catalyzed Cascade Redox‐Neutral C–H Functionalization and Aromatization: Synthesis of Unsymmetrical ortho‐Biphenols

“…Although the oxidative phenolic coupling offers ad irect approach to ortho-biphenols, [3] the synthesis of unsymmetrical ortho-biphenols remains elusive [4] due to homocoupling and poorr egioselectivity.U nsymmetrical ortho-biphenols can be constructed by indirect oxidative coupling of two phenols,i nw hich one coupling partner is oxidized to the quinone derivative and then couples with the other phenolu nder organocatalysis. [5] In addition,s tudies on the synthesis of non-C 2 -symmetical ortho-biphenols via transition metal-catalyzed C-X/C-M cross-coupling [6] or intramolecular C-H/C-X coupling have also been report-ed. [7] However, these approaches require selective ortho-halogenation of phenols and multistep synthesis,thuslimiting theirefficiency.…”