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.