Catalytic amounts of 2,2,6,6-tetramethyl-1-piperidinyloxyl (TEMPO)
are used in combination with
[bis(acetoxy)iodo]benzene (BAIB) as a stoichiometric oxidant in the
conversion of primary and
secondary alcohols to carbonyl compounds. This procedure works
efficiently at room temperature
in almost all common solvents and neat in some cases. This process
exhibits a very high degree of
selectivity for the oxidation of primary alcohols to aldehydes, without
any noticeable overoxidation
to carboxyl compounds, and a high chemoselectivity in the presence of
either secondary alcohols or
of other oxidizable moieties. This procedure allows an easy,
convenient, high-yielding method for
the oxidation of alcohols starting from commercially available
compounds.
The structure and absolute configuration of the marine antithrombotic product dysinosin A was confirmed by total synthesis. The strategy involved disconnections to three subunits, of which two were synthesized from the readily available l-glutamic acid, d-leucine, and d-mannitol. The Grubbs olefin metathesis carbocyclization reaction was utilized to prepare two intermediates.
Homochiral pairs of vicinal diamines and vicinal diols form welldefined crystalline supramolecular assemblies (supraminols) as a result of mutual recognition. X-ray crystallographic analysis shows extensive hydrogen bonding between amine and alcohol groups that results in a hydrophilic inner core and hydrophobic outer peripheral units. The inner core consists of partially or fully hydrogen-bonded amine ± alcohol interactions that lead to a pleatedsheet-or ribbonlike secondary structure. The outer periphery consists of left-or right-handed helical strands of alternating diamine ± diol units, depending on the sense of chirality of the diamine and the diol. High enantiomeric enrichment is possible when an enantiopure diamine and a racemic diol are allowed to interact resulting in a matched homochiral crystalline adduct. In one instance, the occlusion of a molecule of benzene within the assembly was observed. On the basis of competition experiments, some predictions can be made regarding the best matched pairs of diamines and diols, which we have termed supramolecular chirons.
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.