96854-34-1Relevant articles and documents
Copper(I)-Catalyzed Asymmetric Vinylogous Aldol-Type Reaction of Allylazaarenes
Wang, Si-Qing,Liu, Zong-Ci,Yue, Wen-Jun,Yin, Liang
supporting information, p. 4604 - 4608 (2021/01/21)
A vinylogous aldol-type reaction of allylazaarenes and aldehydes is disclosed that affords a series of chiral γ-hydroxyl-α,β-unsaturated azaarenes in moderate to excellent yields with high to excellent regio- and enantioselectivities. With (R,RP)-TANIAPHOS and (R,R)-QUINOXP* as the ligand, the carbon-carbon double bond in the products is generated in (E)-form. With (R)-DTBM-SEGPHOS as the ligand, (Z)-form carbon-carbon double bond is formed in the major product. In this vinylogous reaction, aromatic, α,β-unsaturated, and aliphatic aldehydes are competent substrates. Moreover, a variety of azaarenes, such as pyrimidine, pyridine, pyrazine, quinoline, quinoxaline, quinazoline, and benzo[d]imidazole are well-tolerated. At last, the chiral vinylogous product is demonstrated as a suitable Michael acceptor towards CuI-catalyzed nucleophilic addition with organomagnesium reagents.
Highly diastereo- and enantioselective allylboration of aldehydes using α-substituted allyl/crotyl pinacol boronic esters via in situ generated borinic esters
Chen, Jack L.-Y.,Scott, Helen K.,Hesse, Matthew J.,Willis, Christine L.,Aggarwal, Varinder K.
supporting information, p. 5316 - 5319 (2013/05/21)
Readily available, α-substituted allyl/crotyl pinacol boronic esters often give low E/Z selectivity (with Z favored) in reactions with aldehydes. We found that addition of nBuLi to the pinacol boronic ester followed by trapping of the alkoxide with TFAA leads to an intermediate allyl borinic ester which undergoes allylboration with very high E selectivity. The substrate scope includes primary to tertiary alkyl α-substituents, crotyl substrates, and the previously unreported β-methallyl pinacol boronic esters. The latter give very high Z selectivity under standard conditions which is completely reversed to high E selectivity under the new conditions. Monitoring the reaction by 11B NMR confirmed that the reaction proceeds through a borinic ester intermediate.
Palladium-catalyzed synthesis of enantiomerically pure α-substituted allylboronic esters and their addition to aldehydes
Fernandez, Enrique,Pietruszka, Joerg,Frey, Wolfgang
supporting information; experimental part, p. 5580 - 5589 (2010/11/17)
Tartrate-derived boronic esters 2 can be subjected to palladium-catalyzed carbonyl allylations with SnCl2 to obtain enantiomerically pure α-substituted allylboronic esters 8 and 9. The reaction proceeds regioselectively and with high, simple diastereoselectivity to form anti-products. Their addition to aldehydes yields enantiomerically enriched homoallylic alcohols 17 and 18, respectively. Synthesis, characterization, and a mechanistic rational is presented here.
