Recent contributions from the Baylis-Hillman reaction to organic chemistry

DABCO catalyzed cross-Rauhut-Currier/transesterification reactions of activated alkenes with phenyl acrylates: scope and mechanistic insight

DABCO catalyzed the cross-Rauhut-Currier/transesterification reaction of α-cyano-α,β-unsaturated ketones and aryl acrylates was discovered. The reaction rate law was determined by an integral method under pseudo-first-order reaction conditions, which assisted in proposing the mechanism of cross-Rauhut-Currier reaction promoted by Brønsted acid and establishing the rate-determining step.

Kinetic resolution of allyl fluorides by enantioselective allylic trifluoromethylation based on silicon-assisted C-F bond cleavage

Two birds, one stone! The first kinetic resolution of allyl fluorides was achieved by the development of an organocatalyzed enantioselective allylic trifluoromethylation. Two kinds of chiral fluorinated compounds, which incorporate C*F and C*CF3 units, respectively, can thus be accessed by a single transformation.

The roles of counterion and water in a stereoselective cysteine-catalyzed Rauhut-Currier reaction: a challenge for computational chemistry

The stereoselective Rauhut-Currier (RC) reaction catalyzed by a cysteine derivative has been explored computationally with density functional theory (M06-2X). Both methanethiol and a chiral cysteine derivative were studied as nucleophiles. The complete reaction pathway involves rate-determining elimination of the thiol catalyst from the Michael addition product. The stereoselective Rauhut-Currier reaction, catalyzed by a cysteine derivative as a nucleophile, has also been studied in detail. This reaction was experimentally found to be extremely sensitive to the reaction conditions, such as the number of water equivalents and the effect of potassium counterion. The E1cB process for catalyst elimination has been explored computationally for the eight possible stereoisomers. The effect of explicit water solvation and the presence of counterion (either K(+) or Na(+) ) has been studied for the lowest energy enantiomer pair (1S, 2R, 3S)/(1R, 2S, 3R).

Templated alkylation of hexahistidine with Baylis-Hillman esters

Alkylation of one of the imidazole rings of hexahistidine with Baylis-Hillman esters tethered to nitrilotriacetate residue was achieved in aqueous solutions at neutral pH and at micromolar concentrations in the presence of Ni(2+), Cu(2+), or Zn(2+) cations. The utility of the approach for selective functionalization of His-tagged recombinant proteins was demonstrated by attachment of a fluorescent label to recombinant protein A with an alkynyl group followed by a "click" 1,3-dipolar cycloaddition reaction.

Synthesis, antitubercular and anticancer activity of new Baylis-Hillman adduct-derived N-cinnamyl-substituted isatin derivatives

Baylis–Hillman adduct-derived N-cinnamyl-substituted isatin derivatives were synthesized and evaluated for their antitubercular activity on Mycobacterium tuberculosis H₃₇Rv strain ATCC 27294 by agar dilution method. Anticancer activity for the same compounds was also screened on four different cell lines: Chinese hamster ovary (CHO cells), Colo 205 (human colon cancer), Sup-T1 (human lymphoma) and C6 glioma (rat glioma) by MTT assay method. The compounds (3j–l) have shown significant activity against Mycobacterium strain and the compound 3l has shown specific cytotoxic activity.

Recent developments of ketene dithioacetal chemistry

Ketene dithioacetals are versatile intermediates in organic synthesis. Extensive research, since the last decade, has given rise to new prospects in their chemistry. The objective of this review is twofold: first, to highlight the new prospects in the chemistry of functionalized ketene dithioacetals, and second, to provide an intrinsic link between ketene dithioacetal groups and a variety of other functional groups, which has brought out many new facts that will assist in future designs.

(RC,SFe)-1-[3,5-Bis(trifluoromethyl)phenyl]-3-{1-[2-(diphenylphosphanyl)ferrocenyl]ethyl}thiourea (unknown solvate)

In the molecule of the the title compound, [Fe(C₅H₅)(C₂₈H₂₂F₆N₂PS)], the absolute configuration is R_C,S_Fe. The dihedral angle between the trifluoro­methyl-substituted phenyl ring and the thio­urea plane is 41.8 (9)°. The iron atom is bound to the cyclo­penta­dienyl rings in the typical η⁵-manner in a close to eclipsed conformation. The crystal structure features N—H⋯S hydrogen bonds, with the S atom as an acceptor for both N—H groups, forming a layered arrangement parallel to (1-10). The two –CF₃ groups are each disordered over two positions with refined occupancy rates for the major components of 0.66 (7) and 0.55 (5). The crystal was grown from mixed solvents (n-hexane and ethyl acetate). These solvents are disordered in the crystal and the resulting electron density was found to be uninterpretable. The solvent contribution to the structure factors was taken into account by back-Fourier transformation of all density found in the disordered solvent area using the SQUEEZE routine in PLATON [Spek (2009 ▶). Acta Cryst. D65, 148–155]. The formula mass and density do not take account of the solvent.