Propeller substituents imposing steric restraint on crown ethers
作者:Joyce C. Lockhart、Martin B. McDonnell、William Clegg
DOI:10.1039/c39840000365
日期:——
Crownethers with stericrestraint imposed by a three-bladed propellersubstituent have been synthesized and the X-Ray crystal structures of one example and its NaNCS complex indicate approximately the same conformation of the propeller but quite different conformations of the ether ring in the two; n.m.r. solution spectra indicate that the flipping of the propeller and of the crown moieties are mutually