High-resolution single crystals of a catalytic RNA molecule derived from the sequence of the satellite RNA of tobacco ringspot virus have been obtained. The unitcell volumes of the RNA crystals vary depending on the crystallization conditions and temperature. The best crystal form, when flash frozen, has space group P1 with unit-cell dimensions a --53.08, b --71.81, c ---28.03 A, c~ = 98.43,/3 --104.32 and 3' = 74.54°. This form diffracts to a resolution of 2.4 A. A heavy-atom derivative search is in progress.

Bridging chiral p‐tert‐butylcalix[4]arenes (p‐t‐Bu‐BCC's) with different N‐substituted carbamoyl bridge‐substituents (N,N‐dimethylcarbamoyl, N,N‐diethylcarbamoyl and morpholinocarbonyl) were successfully prepared through anionic ortho‐Fries rearrangement from mono‐O‐carbamates of 1,3‐dipropyl‐p‐tert‐butylcalix[4]arene in 65–75% yield. In addition, p‐t‐Bu‐BCC with two N,N‐dimethylcarbamoyl bridge‐substituents was produced by this method from mono‐O‐carbamate of p‐t‐Bu‐BCC with one N,N‐dimethylcarbamoyl bridge‐substituent in 71% yield. However, the synthesis of p‐t‐Bu‐BCC with additional carbamoyl bridge‐substituents using this method could not be attempted, as the required rearrangement precursor failed to be synthesized. Finally, the racemic p‐t‐Bu‐BCC with morpholinocarbonyl bridge‐substituent was optically resolved into a pair of enantiomers, whose absolute configurations were determined through ROESY analysis and ECD comparison.

A pair of bridging chiral p‐t‐butylcalix[4]arenes (2a and 2b) (were) synthesized from 1 through homologous anionic ortho‐Fries rearrangement, and optically resolved with (1S)‐(+)‐10‐camphorsulfonyl chloride as chiral auxiliary. Bridging chiral p‐t‐butylcalix[4]arene tetrahydroisoquinolines (9a and 9b) as chiral organocatalysts for Henry reaction were designed and synthesized through the structural modification of 2a and 2b, respectively. Compared to the catalytic enantioselectivity of the unmodified tertiary amine (4b: ∼0% ee and 63% yield), those of the tetrahydroisoquinoline derivatives (9b: up to 13.4% ee and 96% yield) were distinctly enhanced. Although the increase magnitude of the catalytic ee is not remarkable, these catalytic results prove that the conformation inversion of calix[4]arene skeleton and the rotational freedom reduction of catalytic amine group indeed bring beneficial effects on the catalytic stereoselectivity.

A pair of diastereomers 2 a and 2 b were synthesized from the conjugation of bridging chiral de‐tert‐butylcalix[4]arene racemate 1 and (1S)‐(+)‐10‐camphorsulfonyl chloride. The diastereomeric separation by crystallization was explored in different solvents, temperature and time. The optimal crystallization procedures can afford them in a desirable yield, de and purity. A pair of enantiomers 1 a and 1 b were subsequently obtained after their hydrolysis. Moreover, their absolute configurations were determined by X‐ray crystallographic analysis. The crystallization results can match the large‐scale preparation of optically pure de‐tert‐butylcalix[4]arene in laboratory and industry.