Identification of diastereomeric cyclobutyl dimers in a mixture by NMR

摘要

The product obtained in a reaction of 3-methyl-4-nitro-5-styrylisoxazole (1) has been shown to be a diastereomeric mixture of two cyclobutyl dimers by NMR". A combination of ~1H, ~(130C spectra including DEFT, ASIS, 2D COSY and nOe techniques has established that centrosymmetric cyclobutane (2) and the isomer (8) with plane of symmetry are in 2:1 proportion.