Substituted oxocene derivatives have been synthesized by Lewis acid catalyzed reactions of ε-hydroxy-alkene and substituted aromatic aldehydes. The Cu(OTf)2-bis-phosphine catalyzed reaction typically provides substituted dihydropyran derivatives through an olefin-migration, followed by a Prins cyclization. The corresponding reaction catalyzed by TMSOTf or BF3·OEt2 provided eight-membered cyclic ethers, oxocenes, selectively. This methodology provides convenient access to a variety of 2,4,8-trisubstituted oxocenes in good yields and excellent diastereoselectivities.
Three molybdenum(VI)
cis
-dioxo catalysts (
8
–
10
) were synthesized
with the goal of
developing stable and selective oxidation catalysts for sulfoxidation.
Their reactivities were investigated with a variety of substrates.
We have demonstrated the usefulness of these catalysts for the chemoselective
sulfoxidation of sulfides in the presence of reactive moieties, which
has important applications for total synthesis processes. Notably,
these catalysts are able to oxidize compounds analogous to sulfur
mustard and can be used as an alternative to sodium periodate or
meta
-chloroperoxybenzoic acid (
m
-CPBA)
for the oxidation of various organic sulfides without sacrificing
total conversion. As the catalysts are tolerant of water and hydrogen
peroxide, they allow for the design of completely green oxidation
reactions, particularly for sulfur-containing amino acids.
Cyclic ethers are widely abundant in natural products. Cyclic ether templates are also utilized in drug design and medicinal chemistry. Although the synthetic processes for this class of compounds have been studied extensively with respect to five- and six-membered rings, medium-sized cyclic ethers are synthetically more challenging due to a variety of factors. Herein, we report our results on the Lewis acid catalyzed synthesis of medium-sized cyclic ethers in a diastereoselective manner.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.