Synthesis of enantiomerically pure helicene like bis-oxazines from atropisomeric 7,7′-dihydroxy BINOL: preliminary measurements of the circularly polarized luminescence
摘要:
A racemic sample of 2,2',7,7'-tetrahydroxy-1,1'-binaphthyl was resolved with (S)-proline and the separated enantiomers were independently converted to atropisomeric bis-oxazines by aromatic Mannich reaction. These chirally pure oxazines were then converted to the helicene like cyclic ethers. The circularly polarized luminescence (CPL) profile was consistent with the isolation of the targeted helical-like molecules in optically pure form, prepared from the achiral primary amines. The compounds of interest displayed active and opposite CPL activities for each set of the helicene like isomers (P)-/(M)-3 and (P)-/(M)-5. (c) 2014 Elsevier Ltd. All rights reserved.
作者:Harish R. Talele、Sibaprasad Sahoo、Ashutosh V. Bedekar
DOI:10.1021/ol301267r
日期:2012.6.15
A series of novel 1,3-oxazines were prepared to construct a helical framework. The 1,3-oxazine attached to the phenanthrene unit showed a small bite angle theta (similar to 12 degrees), while the units attached to [4]helicene showed a larger theta (similar to 35 degrees) and exhibited helical isomers at ambient conditions. The diastereomers of the third type of helicene-like bis-oxazine attached to binaphthyl were easily separable and showed good thermal stability. All four diastereomers of bis-helicene were synthesized, and their absolute configuration was established.
Synthesis of enantiomerically pure helicene like bis-oxazines from atropisomeric 7,7′-dihydroxy BINOL: preliminary measurements of the circularly polarized luminescence
作者:M. Shyam Sundar、Harish R. Talele、Hemant M. Mande、Ashutosh V. Bedekar、Roberto C. Tovar、Gilles Muller
DOI:10.1016/j.tetlet.2014.01.108
日期:2014.3
A racemic sample of 2,2',7,7'-tetrahydroxy-1,1'-binaphthyl was resolved with (S)-proline and the separated enantiomers were independently converted to atropisomeric bis-oxazines by aromatic Mannich reaction. These chirally pure oxazines were then converted to the helicene like cyclic ethers. The circularly polarized luminescence (CPL) profile was consistent with the isolation of the targeted helical-like molecules in optically pure form, prepared from the achiral primary amines. The compounds of interest displayed active and opposite CPL activities for each set of the helicene like isomers (P)-/(M)-3 and (P)-/(M)-5. (c) 2014 Elsevier Ltd. All rights reserved.