Tin(II) chloride dihydrate-mediated deacetalisation- bicyclisation procedures for the construction of novel polycyclic heterocycles from amides possessing a pendant acetal group are re- ported. Optimisation and scoping studies are described; using this methodology, a range of known, and novel, ring-fused heterocyclic systems have been prepared, some in enantiomerically pure form.
A novel chiral 1,5‐N,N‐bidentate ligand based on a spirocyclic pyrrolidine oxazoline backbone was designed and prepared, and it coordinates CuBr in situ to form an unprecedented catalyst that enables efficient oxidative cross‐coupling of 2‐naphthols. Air serves as an external oxidant and generates a series of C1‐symmetric chiral BINOL derivatives with high enantioselectivity (up to 99 % ee) and good
Various orthodiazonaphthoquinones (1-diazo-2(1H)-naphthalenones and 2-diazo-1(2H)-naphthalenones) were synthesized using the diazo-transfer reaction between the appropriate naphthol and 2-azido-1,3-dimethylimidazolinium chloride (ADMC). The ADMC was prepared by the reaction between 2-chloro-1,3-dimethylimidazolinium chloride and sodium azide. The diazo-transfer reaction selectively introduced the diazo group at the C(2) position of 1-naphthol or the C(1) position of 2-naphthol. The naphthalenediols that were tested, except for 1,3-naphthalenediol, also reacted with ADMC to afford the corresponding monodiazotized compound. X-ray analyses suggested that the diazonaphthoquinones did not have diazoniumnaphtholate structures but had diazocarbonyl structures.
Cu(I)-catalyzed asymmetric oxidative cross-coupling of 2-naphthol derivatives
作者:Tomohisa Temma、Bunpei Hatano、Shigeki Habaue
DOI:10.1016/j.tet.2006.06.069
日期:2006.9
asymmetric oxidativecoupling reaction between 2-naphthol or binaphthol derivatives and 3-hydroxy-2-naphthoate derivatives with the copper(I)-(S)-(−)-isopropylidenebis(4-phenyl-2-oxazoline) catalyst was carried out. The reaction proceeded in a highly cross-coupling selective manner (≤99.7%) to produce the binaphthyl or quaternaphthyl derivative in good yield (≤92%) with enantioselectivity of up to 74%
3‐Substituierte 2‐Naphtholderivate ergeben mit N‐Methyl‐2‐naphthylamin und Paraformaldehyd in guten Ausb. entspr. Spirocyclohexadienone, wobei auch 9‐Phenanthrol diesem Reaktionstyp zugänglich ist. Grundsätzlich liefern 4‐substituierte 1‐Naphthole ebenfalls Spiroketone, die jedoch labiler sind und in geringerem Ausmaß anfallen. Die Umsetzung der Spirocyclohexadienone mit Protonensäuren, Carbonylreagenzien