Open AccessTurning Spiroketals Inside Out: A Rearrangement Triggered by an Enol Ether Epoxidation
Author(s) -
Lorenc Chris,
Saurí Josep,
Moser Arvin,
Buevich Alexei V.,
Williams Antony J.,
Williamson R. Thomas,
Martin Gary E.,
Peczuh Mark W.
Publication year - 2015
Publication title -
chemistryopen
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.644
H-Index - 29
ISSN - 2191-1363
DOI - 10.1002/open.201500122
Subject(s) - cycloisomerization , enol , chemistry , enol ether , molecule , ether , characterization (materials science) , combinatorial chemistry , stereochemistry , organic chemistry , nanotechnology , catalysis , materials science
Spiroketals organize small molecule structures into well‐defined, three‐dimensional configurations that make them good ligands of proteins. We recently discovered a tandem cycloisomerization–dimerization reaction of alkynyl hemiketals that delivered polycyclic, enol‐ether‐containing spiroketals. Here we describe rearrangements of those compounds, triggered by epoxidation of their enol ethers that completely remodel their structures, essentially turning them “inside out”. Due to the high level of substitution on the carbon skeletons of the substrates and products, characterization resorted to X‐ray crystallography and advanced computation and NMR techniques to solve the structures of representative compounds. In particular, a new proton‐detected ADEQUATE NMR experiment (1,1‐HD‐ADEQUATE) enabled the unequivocal assignment of the carbon skeleton of one of the new compounds. Solution of the structures of the representative compounds allowed for the assignment of product structures for the other compounds in two separate series. Both the rearrangement and the methods used for structural determination of the products are valuable tools for the preparation of characterization of new small molecule compounds.