Synthesis of Pentaoxa[5]peristylanes

Abstract

The synthesis of alkyl-substituted pentaoxa[5]peristylanes has been accomplished by ozonolysis of 2,3-bis-endo-7-anti-triacylnorbornenes 6a-d and by direct chemical transformation of the tetraacetal tetraoxa cages 11 and 12. Various reaction conditions have been used to optimize the overall yield for the synthesis of methyl group substituted pentaoxa[5]peristylane 7d. Ozonolysis of 6d in CDCl(3) at -78 degrees C without reduction was performed to study the ozonolysis chemistry of the triacylnorbornenes 6a-d. The synthesis of the parent (unsubstituted) compound 25 of pentaoxa[5]peristylane has been accomplished by a three-step efficient sequence with a maximum 45% overall yield via ozonolysis of the dihemiacetal 24. The structure of pentaoxa[5]peristylanes was proven by X-ray analysis of the parent compound 25. The syntheses of the triacetal tetraoxa cage 26, a new type of oxa cage, and a new entry for the synthesis of the parent compound 33 of tetraacetal tetraoxa cages were also demonstrated.

anti-Oligoannelated THF Moieties: Synthesis via Push−Pull-Substituted Cyclopropanes

“…Cyclic and acyclic oligospiro-THF systems such as 3 and 4 were synthesized and revealed deeper insights into the gauche effect . Highly elegant synthetic routes led to the creation of so-called oxa-bowls of type 5 and 6 . Systems of such a molecular architecture are not only known for three and five, but also for four and six syn -fused THF moieties …”

“…Highly elegant synthetic routes led to the creation of so-called oxa-bowls of type 5 and 6 . Systems of such a molecular architecture are not only known for three and five, but also for four and six syn -fused THF moieties …”

Thiabowls: Synthesis, Molecular Structure, and Novel Supramolecular Architecture of Trithia-[3]-Peristylane

“…In pursuit of the target structures 1b , c , d − 4b , c , d , we have recently accomplished the synthesis of triaza-[3]-peristylane 1c ,2a tetraoxa-[4]-peristylane 2b ,2b tetrathia-[4]-peristylane 2d ,2c and pentaoxa-[5]-peristylane 3b . 2d-f, Oxaperistylanes 2b and 3b have been found to show a very interesting supramolecular architecture in the solid-state dictated by a network of CH···O interactions. 2b,d-f, On the other hand, tetrathia-[4]-peristylane 2d has a multicolumnar arrangement in the solid-state sustained by S···S and CH···S interactions 2c…”

Oxa Bowls: Synthesis of New Tetraoxa-Cages and Their C−H···O-Mediated Solid-State Architecture

“…We have recently conceived of [ n ]-hetero[ n ]peristylanes ( n -hetero-bowls) 1 as heterocyclic analogues of [ n ]peristylanes . This novel class of molecular entities consists of an [ n ]-membered carbocyclic base and a [2 n ]-membered heterocyclic rim with [ n ]-heteroatoms and has an overall C nv symmetry. − The walls of these [ n ]hetero[ n ]peristylanes are exclusively composed of five-membered rings. As a part of wider interest in these hetero-bowls, we have initially directed out attention toward oxa-bowls 1 (X = O) and following the strategy of cascade intramolecular acetalization in all cis -[ n ]formyl[ n ]cycloalkanes 2 , we have reported the synthesis of tetraoxa[4]peristylane 3 ,3b pentaoxa[5]peristylane 4 , 4a,b and a close precursor of hexaoxa[6]peristylane 5 .…”