Peptide‐Catalyzed Fragment Couplings that Form Axially Chiral Non‐
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C
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‐Symmetric Biaryls
作者:Gavin Coombs、Marcus H. Sak、Scott J. Miller
DOI:10.1002/anie.201913563
日期:2020.2.10
We have demonstrated that small, modular, tetrameric peptides featuring the Lewis-basic residue β-dimethylaminoalanine (Dmaa) are capable of atroposelectively coupling naphthols and ester-bearing quinones to yield non-C2 -symmetric BINOL-type scaffolds with good yields and enantioselectivity. The study culminates in the asymmetric synthesis of backbone-substituted scaffolds similar to 3,3'-disubstituted
Synthesis of xanthoneO-glycosides. Part III. Synthesis of 1- and 8-O-?-D-glycosides of 5-O-methyl- and de-O-methylbellidifolin
作者:Barbara Vermes、Otto Seligmann、Hildebert Wagner
DOI:10.1002/hlca.19850680832
日期:1985.12.18
The unambiguous synthesis of three naturally occurring and biologically active xanthone 1-O and 8-O-β-D-glucosides of 5-O-methyl- and de-O-methylbellidifolin (2–4) was accomplished. The protected xanthone aglycones having only a single reactive OH group were prepared by selective benzylation, methylation, and debenzoylation reactions. An unexpected stability of the 1-MeO group towards demethylation
完成了3种天然存在且具有生物活性的蒽酮1- O和8 - O -β-D-葡萄糖苷(5- O-甲基-和去-O-甲基bellidifolin(2-4)的明确合成)。通过选择性苄基化,甲基化和脱苯甲酰化反应制备仅具有单个反应性OH基团的被保护的蒽酮苷元。观察到1-MeO基团对去甲基化的出乎意料的稳定性。
Cobalt-catalyzed arylation and alkenylation of alpha-bromo eneformamides and enecarbamates by cross-coupling with organic bromides: Application to the synthesis of functionalized piperidines and azepanes
作者:Daniel P. Bassler、Amir Alwali、Laura Spence、Oliver Beale、Timothy K. Beng
DOI:10.1016/j.jorganchem.2015.01.001
日期:2015.3
α-arylated and alkenylated piperidine and azepane derivatives has been accomplished through cross-coupling of α-bromo eneformamides or enecarbamates with feedstock organic halides such as aryl and vinyl bromides, under cobalt catalysis. The coupling products, which themselves are synthetic intermediates for accessing other functionalized piperidines and azepanes are obtained in good to excellent yields
Organocatalytic Enantioselective Synthesis of Atropisomeric Aryl‐
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‐Quinones: Platform Molecules for Diversity‐Oriented Synthesis of Biaryldiols
作者:Ye‐Hui Chen、Heng‐Hui Li、Xiao Zhang、Shao‐Hua Xiang、Shaoyu Li、Bin Tan
DOI:10.1002/anie.202004671
日期:2020.7.6
Presented here is a class of novel axiallychiral aryl‐p ‐quinones as platform molecules for the preparation of non‐C2symmetric biaryldiols. Two sets of aryl‐p ‐quinone frameworks were synthesized with remarkable enantiocontrol by means of chiral phosphoric acid catalyzed enantioselective arylation of p ‐quinones by central‐to‐axialchirality conversion. These aryl‐p ‐quinones were then used to access
Simple quinine as an organocatalyst mediates the addition of various naphthols to halogenated quinones to afford non‐C2‐symmetrical, axially chiral biaryl products, which are promising compounds as chiral ligands and organocatalysts. The rotational barrier required to have two distinct atropisomers has been evaluated in the products generated from the addition of naphthols to various quinones by means