Conformational analysis of 12,12,21,21-tetradeuterio-1,4-dioxa-[4.3.3](1,3,5)Cyclophane

[36](1,2,3,4,5,6)CyclophaneA Molecular Pinwheel and Its Correlated Inversion: NMR and Energetic Considerations

“…The trimethylene bridges invert rapidly at room temperature, and a 10.9 kcal mol -1 barrier for the degenerate 2a ⇌ 2b interconversion (Scheme ) was deduced from variable temperature NMR spectroscopy − However, for the inversion of a hexatuply bridged cyclophane no intermediates were characterized experimentally or even suggested. The title compound 2 has been proposed as a possible precursor for the unknown propella[3 6 ]prismane ( 3 ), which might be achieved by successive [2 + 2] photochemical ring closures. ,, We studied the molecular structure and the magnetic properties of 2 , its degenerate inversion, and its reaction to yield 3 using quantum chemical techniques.…”

Diastereoselective alkylation of (3S)- and (3R)-3-methylpiperazine-2,5-dione derivatives. A convenient approach to both (S)- and (R)-alanine

“…Subsequent hydrolytic cleavage leads to amino acids in high ee. 2 As part of a program aimed at the use of piperazine-2, 5-diones (containing a chiral group bonded to each of the N-atoms) in asymmetric synthesis, we have devised a new approach to the synthesis of -amino acids in high optical purity by the alkylation of a chiral enolate anion. Similar…”

Synthesis and conformational studies of 9-benzyloxy-18-substituted [3.3]metacyclophanes

“…2,[11][12] A conformational study of the parent [3.3]metacyclophanes revealed that the most stable conformation has the syn geometry with a chair-chair arrangement of the trimethylene chains. [13][14][15][16][17][18] Cyclophanes have so many important applications due to flexible structure in theoretical study. Therefore, there is a continuous effort to synthesize novel cyclophanes through efficient and simple routes.…”