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Upstream product

• 17763-95-0 2,2'-bis-<<(trifluoromethyl)sulfonyl>oxy>biphenyl 
• 535925-40-7 bis(3,5-di-tert-butyl-4-methoxy-phenyl)phosphine oxide 
• 1806-29-7 2,2'-dihydroxybiphenyl 
• 1516-96-7 4-bromo-2,6-di-tert-butylanisole 

Relevant academic research and scientific papers

Palladium(0)-Lithium Iodide Cocatalyzed Asymmetric Hydroalkylation of Conjugated Enynes with Pronucleophiles Leading to 1,3-Disubstituted Allenes

Axially chiral 1,3-disubstituted allenes were synthesized via hydroalkylation of alkyl- or aryl-substituted conjugated enynes (readily prepared via a Sonogashira reaction) with pronucleophiles such as dimethyl malonate under the cocatalysis of DTBM-SEGPHOS-ligated palladium and lithium iodide. Although the palladium catalyst ligated with (S)-DTBM-SEGPHOS prefers the formation of (R)-1,3-disubstituted allenes, lithium iodide recovers and increases the intrinsic selectivity producing (S)-allenes by promoting the isomerization of the exo-alkylidene-π-allylpalladium intermediate prior to the nucleophilic substitution step.

Palladium-Catalyzed Sequential Twofold Nucleophilic Substitution on 3-Bromopenta-2,4-dienyl Phosphate: Preparation of C1- And C2-Symmetric Doubly Functionalized Allenes

Readily available 3-bromopenta-2,4-dienyl esters (1x, acetate; 1y, benzoate; 1z, diethyl phosphate) were applied to the palladium-catalyzed reaction with various soft nucleophiles. The reaction proceeded through the twofold nucleophilic substitution via formal SN2′- and SN2-processes, giving the various doubly functionalized allenes 2 in good yields. In the reactions of carboxylates 1x and 1y, the first substitution took place at the C-Br bond to form (allenyl)methyl ester intermediates 3. Because the second substitution on 3 proceeded faster than the first substitution on 1x or 1y, 3 was not isolable, and C2-symmetric allenes 2 were obtained even in the presence of remaining 1x and 1y. On the other hand, the phosphate moiety was more reactive than the C-Br moiety in 1z. The initial products from 1z were 5-Nu-3-bromopenta-1,3-dienes 4, which were less reactive than 1z. Monosubstitution products 4 were isolable, and the stepwise introduction of two different Nu groups in C1-symmetric allenes 2 was realized starting with 1z under the controlled reaction conditions. By the use of a chiral palladium catalyst, axially chiral doubly functionalized allenes were obtained up to 95% ee.

General synthetic route to chiral flexible biphenylphosphine ligands: The use of a chiral additive enables the preparation and observation of metal complexes incorporating the enantiopure form

equation presented The enantio-and diastereomerically pure metal complex of a chirally flexible BIPHEP ligand is obtained through enantiomer-selective coordination of a BIPHEP-Ru complex with enantiopure 3,3′-dimethyldiaminobinaphthyl, DM-DBN, followed by