Conjugate addition reaction of various nucleophiles across the vinyl group of 2-chloro-4-vinylpyrimidine, 2-chloro-4-(1-phenylvinyl)pyrimidine and 2-chloro-4-vinylquinazoline provides the corresponding 2-chloro-4-(2-substituted ethyl)pyrimidines and 2-chloro-4-(2-substituted ethyl)quinazolines. Treatment of these products, without isolation, with N-methylpiperazine results in nucleophilic displ...

[reaction: see text] Using a combination of chiral monodentate phosphoramidite ligands in the rhodium-catalyzed conjugate addition of boronic acids to three different substrates, we have shown for the first time that the ligand combination approach is applicable for C-C bond formation. Chiral catalysts based on hetero-combinations of ligands are found to be more effective than the homo-combinat...

An efficient method for the N-heterocyclic carbene (NHC)-catalyzed conjugate addition of acetyl anions to various α,β-unsaturated acceptors (Stetter reaction) has been optimized by using 2,3-butandione (biacetyl) as an alternative surrogate of acetaldehyde. The disclosed procedure proved to be compatible with microwave dielectric heating for reaction time reduction and with the use of different...

A method is described for the automated analysis of urinary 11-deoxy-17-oxo steroids from hydrolyzed conjugate extracts. Steroid conjugates are extracted manually on an Amberlite XAD-2 column and hydrolyzed with f3-glucuronidase at 62#{176}C for 90 mm. After addition of alkali, the samples are transferred to the AutoAnalyzer where the steroids are extracted into isooctane and estimated colorime...

γ,δ-Unsaturated alcohols are prepared efficiently in two steps from o-hydroxycinnamaldehyde. The TMSOTf-mediated reaction of the γ,δ-unsaturated alcohols with aldehydes creates two oxygen heterocycles and three new stereocenters in a single pot. The approach is versatile, and by varying the boronic acid, Grignard reagent, and aldehyde, different substituents may be introduced, while use of a ch...

Oxindoles with adjacent tetrasubstituted stereocenters were obtained in high yields and stereoselectivities by organocatalyzed conjugate addition reactions of monothiomalonates (MTMs) to isatin-derived N-Cbz ketimines. The method requires only a low catalyst loading (2 mol %) and proceeds under mild reaction conditions. Both enantiomers are accessible in good yields and excellent stereoselectiv...

One pot syntheses of furan, thiophene, and pyrrole were accomplished by oxidative deacetylation using Mn(III)/Co(II) catalysts and the Paal-Knorr reaction from 1,5-dicarbonyl compounds, which are prepared from the conjugate addition of ethyl acetoacetate to α,β-unsaturated carbonyl compounds. The oxidative deacetylation and reductive cyclization of β-ketoesters derived from ethyl acetoacetate a...

An efficient approach for the synthesis of functionalized 4-substituted-2-amino-3-cyano-4H-chromenes moderate to high yields (up to 98%) has been achieved via a tandem K2CO3 catalyzed conjugate addition-cyclization reaction of malononitrile and a range of Knoevenagel adducts previously formed from oxindole, pyrazolone, nitromethane, N,N-dimethylbarbituric acid or indanedione. This methodology d...

The development of an efficient catalytic system for enantioselective carbon-carbon bond formation by 1,4-addition of organometallic reagents (organolithium, Grignard, and organozinc reagents) to enones is a major challenge in organic synthesis. This Account presents the breakthrough realized in this field using chiral phosphoramidite ligands for copper-catalyzed dialkylzinc additions. Applicat...

The highly enantioselective direct organocatalytic conjugate addition of aldehydes to maleimides is presented.