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Journals and Conferences
S-Alkyl, S-aryl, and S-vinyl thiosulfate sodium salts (Bunte salts) react with Grignard reagents to give sulfides in good yields. The S-alkyl Bunte salts are prepared from odorless sodium thiosulfate by an SN2 reaction with alkyl halides. A Cu-catalyzed coupling of sodium thiosulfate with aryl and vinyl halides was developed to access S-aryl and S-vinyl… (More)
Structure-activity relationship analysis of synthetic analogues of curacin A revealed the lack of activity of traditional heterocyclic replacements of the thiazoline ring or cyclopropyl analogues of the core diene segment. The significance of the C(3)-C(4)-(Z)-alkene geometry was established, and a novel oxime analogue was designed that displays biological… (More)
Many natural and synthetic compounds bind to tubulin, an ubiquitous globular protein that provides the building blocks for the cellular microtubule network that controls chromosome segregation during mitosis, vesicle movements, intracellular transport of organelles, ciliar and flagellar movement, and maintenance of cell shape. Since the isolation of the… (More)
A novel two-step synthesis of substituted 2-formylpyrroles is described. Aldol adducts of ketones and 4-formyloxazole undergo a dehydration/oxazole hydrolysis/cyclization cascade on sequential treatment with MsCl/Et3N and aqueous NaOH to yield 5-substituted and 4,5-disubstituted 2-formylpyrroles. The methodology was extended to an N-benzyl thiazolium salt.
[reaction: see text]. A novel N-heterocyclic carbene (NHC) catalyzed trifluoromethylation reaction of carbonyl compounds was discovered. Both enolizable and nonenolizable aldehydes and alpha-keto esters undergo facile trifluoromethylation with TMSCF3 at room temperature in the presence of only 0.5-1 mol % of the commercially available NHC (1), providing… (More)
Azaindoles (also called pyrrolopyridines) constitute essential subunits in many pharmaceutically important compounds. The synthesis of azaindoles has been a great synthetic challenge for chemists. Many classical methods for indole synthesis (such as Fischer and Madelung cyclizations) often cannot be effectively applied to the synthesis of the corresponding… (More)
A general and efficient zinc-alkoxide-catalyzed allylation of a diverse array of ketones with allyl boronates is presented. The methodology is effective with 2 mol % of catalyst and with relatively short reaction times. Studies of the key exchange process are presented, which support a cyclic transition state for the boron to zinc exchange.
Primary and secondary (enolizable) carboxylic acids were converted in a single step to trifluoromethyl ketones. Treatment of the acid with 2.2 equiv of LDA generated an enediolate that was trifluoroacetylated with EtO(2)CCF(3). Quenching the reaction mixture with aqueous HCl resulted in rapid decarboxylation and provided the trifluoromethyl ketone product… (More)
The highly enantio- and regioselective copper catalyzed asymmetric propargylation of aldehydes with a propargyl borolane reagent is reported. The methodology demonstrated broad functional group tolerance and provided high enantioselectivities for aliphatic, vinyl, and aryl aldehydes. The utility of the TMS homopropargylic alcohols was demonstrated by the… (More)
N-Heterocyclic carbenes were found to be highly effective organocatalysts in activating TMSCN for facile cyanosilylation of carbonyl compounds. Cyano transfer from TMSCN to aldehydes and ketones proceeds at room temperature in the presence of only 0.01-0.5 mol % of N-heterocyclic carbene (1), leading to a range of trimethylsilylated cyanohydrins in very… (More)