Carbon-13 magnetic resonance of hydroaromatics. II. Conformation of Tetralin and tetrahydroanthracene and their methyl derivatives
作者:Frederick G. Morin、W. James Horton、David M. Grant、Don K. Dalling、Ronald J. Pugmire
DOI:10.1021/ja00350a042
日期:1983.6
Carbon-13 chemical shift data have been acquired for 36 methylated tetralins and tetrahydroanthracenes. A least-squares regression analysis has been undertaken on the ring carbons of compounds of unequivocal conformation to determine methyl substituent parameters for the two distinct aliphatic positions and the results have been used to estimate the position of equilibrium of conformationally mobile
Catalytic activation of carbon–carbon bonds in cyclopentanones
作者:Ying Xia、Gang Lu、Peng Liu、Guangbin Dong
DOI:10.1038/nature19849
日期:2016.11
we report a general approach to the catalytic activation of C–C bonds in simple cyclopentanones and some cyclohexanones. The key to our success is the combination of a rhodium pre-catalyst, an N-heterocyclic carbene ligand and an amino-pyridine co-catalyst. When an aryl group is present in the C3 position of cyclopentanone, the less strained C–C bond can be activated; this is followed by activation of
Distal-Bond-Selective C−C Activation of Ring-Fused Cyclopentanones: An Efficient Access to Spiroindanones
作者:Ying Xia、Jianbo Wang、Guangbin Dong
DOI:10.1002/anie.201611642
日期:2017.2.20
A site‐selective rhodium‐catalyzed C−C activation of ring‐fused cyclopentanones was achieved to afford efficient access to a range of spiroindanones. The use of bulky 2‐amino‐6‐picoline as a cocatalyst is key to the excellent selectivity of this C−C bond cleavage in cyclopentanones.
An efficient, quantitative deracemization strategy for optically inactive allylic cycloalkanols has been achieved using the biphasic halogenative semi-pinacol reaction protocol. The resultant β-halo spiroketones, containing three contiguous stereogenic centers, were easily recovered with high diastereomeric and enantiomeric purities following conventional silica gel chromatography. The optically active products could be further manipulated chemically, affording synthetically interesting scaffolds with complete preservation of stereoisomeric integrity.