2-Alkyl-3-chloro(bromo)tetrahydrofurans

The reaction ofRS(SR)-2,3-dibromo- and 2,3-dichlorotetrahydrofurans with ethylmagnesium bromide in ether was investigated. It was shown that the main reaction products are 2-ethyl-3-bromotetrahydrofuran (27%) and 3-bromo-2-(2-ethyl-3-tetrahydrofuryl)tetrahydrofuran (65%) in the first case and 2-ethyl-3-chlorotetrahydrofuran (33%) and 3-chloro-2-(3-chloro-2-tetrahydrofuryl)tetrahydrofuran (65%) in the second.N. D. Zelinskii Institute of Organic Chemistry, Russian Academy of Sciences, 117913 Moscow. I. M. Gubkin Moscow Institute of Petroleum and Gas, 111917 Moscow. Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 6, pp. 1430–1434, June, 1992.     

Optical Rotatory Feature of （R or S）—1,1’—Binaphthalene—2,2’—diol（BINOL）in various Solvents

The changes of the specific rotation and sign of optically active BINOL have been studied in polar/non-polar solvents and at the different pH values of solvent.It is considered that these changes are determined by the equilibriurn studies between cisoid and transoid conformations of BINOL with the same configuration(R or S) which related to the change of the dihedral angle between two naphthalene ring planes of BINOL.     

Helix formation of poly(phenylacetylene) derivatives bearing amino groups at the meta position induced by optically active carboxylic acids

Two novel phenylacetylene derivatives bearing diethylaminomethyl groups at the meta position on phenyl groups [3‐(N,N‐diethylaminomethyl)phenyl]acetylene ( 1 ) and [3,5‐bis(N,N‐diethylaminomethyl)phenyl]acetylene ( 2 ) were synthesized and polymerized with [Rh(nbd)Cl]₂ (nbd: norbornadiene). Both monomers gave highly cis–transoidal stereoregular polymers that exhibited an induced circular dichroism (ICD) in the UV–visible region, probably because of a prevailing one‐handed helical conformation upon complexation with optically active carboxylic acids such as mandelic acid and lactic acid. The sign of the Cotton effects reflected the absolute configuration of the chiral acids. Therefore, these polymers can be used as a novel probe for determining the configuration of chiral acids. The polymers were stable in the presence of chiral acids in solution. The poly‐ 1 complexed with chiral acids exhibited a split‐type ICD, whereas the poly‐ 2 complexed with chiral acids showed a different, non‐split‐type ICD. The ICD pattern of the poly‐ 1 /chiral acids complexes dramatically changed with an increase in the concentration of the chiral acids, thus showing a non‐split‐type ICD similar to those of the poly‐ 2 /chiral acid complexes. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3180–3189, 2001