Host-guest complexation. 55. Guest capture during shell closure

We have synthesized seven new carceplexes involving two different hosts and six different guests that are soluble in organic solvents. They were prepared by shell closures of cavitands in 4-fold S N 2 reactions to give carcerands in 20-32% yeidls. High structural recognition for encapsulation of the more polar component in mixtures with benzene as a cosolvent was shown in the shell closures. Incarcerated molecules included two CH 3 OH, wo CH 3 CN, CH 3 CH 2 OH, (CH 3 ) 2 NCHO, CH 3 COC-H 2 CH 3 and CH 3 CH 2 COCH 2 CH 3 . All carcerands except H•CH 3 CN•NCCH 3 (2) were fully characterized. The degrees of rotational freedom of the guests relative to the host were studied with 1 H NMR spectral techniques