Amino acid-based synthesis of trifluoromethylalkene dipeptide isosteres by alcohol-assisted nucleophilic trifluoromethylation and organozinc-copper-mediated S(N)2' alkylation

Nickel-Catalyzed Selective C(sp2 )-F Bond Alkylation of Industrially Relevant Hydrofluoroolefin HFO-1234yf

The selective transition-metal catalyzed C-F bond functionalization of inexpensive industrial fluorochemicals represents one of the most attractive approaches to valuable fluorinated compounds. However, the selective C(sp2 )-F bond carbofunctionalization of refrigerant hydrofluoroolefins (HFOs) remains challenging. Here, we report a nickel-catalyzed selective C(sp2 )-F bond alkylation of HFO-1234yf with alkylzinc reagents. The resulting 2-trifluoromethylalkenes can serve as a versatile synthon for diversified transformations, including the anti-Markovnikov type hydroalkylation and the synthesis of bioactive molecule analogues. Mechanistic studies reveal that lithium salt is essential to promote the oxidative addition of Ni0 (Ln ) to the C-F bond; the less electron-rich N-based ligands, such as bipyridine and pyridine-oxazoline, feature comparable or even higher oxidative addition rates than the electron-rich phosphine ligands; the strong σ-donating phosphine ligands, such as PMe3 , are detrimental to transmetallation, but the less electron-rich and bulky N-based ligands, such as pyridine-oxazoline, facilitate transmetallation and reductive elimination to form the final product.

Rapid access to diverse, trifluoromethyl-substituted alkenes using complementary strategies

Two synergistic approaches to the facile assembly of complex α-trifluoromethyl alkenes are described. Using α-trifluoromethyl-β-silyl alcohols as masked trifluoromethyl alkenes, cross-coupling or related functionalization processes at distal electrophilic sites can be executed without inducing Peterson elimination. Subsequent Lewis acidic activation affords functionalized α-trifluoromethyl alkenes. Likewise, the development of a novel α-trifluoromethylvinyl trifluoroborate reagent complements this approach and allows a one-step cross-coupling of (hetero)aryl halides to access a broad array of complex α-trifluoromethyl alkenes.

Copper-catalyzed β-trifluoromethylation of conjugated hydrazones

The Cu-catalyzed direct β-trifluoromethylation of α,β-unsaturated aldehyde N,N-dibenzylhydrazones with Togni hypervalent iodine reagent is described. The reaction yields stereodefined CF3-alkenyl derivatives under mild conditions and is proposed to proceed via a radical process.

Methylenation of perfluoroalkyl ketones using a Peterson olefination approach

An operationally simple, inexpensive, and rapid route for the olefination of a wide array of trifluoromethyl ketones to yield 3,3,3-trifluoromethylpropenes is reported. Using a Peterson olefination approach, the reaction gives good to excellent yields of the alkene products and can be performed without purification of the β-hydroxysilyl intermediate. The reaction can be extended to other perfluoroalkyl substituents and is easily scaled up. The alkenes prepared can be readily transformed into a variety of other perfluoroalkyl-containing compounds.

Small molecule inhibitors of CXCR4

CXCR4 is a G-protein-coupled receptor involved in a number of physiological processes in the hematopoietic and immune systems. The SDF-1/CXCR4 axis is significantly associated with several diseases, such as HIV, cancer, WHIM syndrome, rheumatoid arthritis, pulmonary fibrosis and lupus. For example, CXCR4 is one of the major co-receptors for HIV entry into target cells, while in cancer it plays an important role in tumor cell metastasis. Several promising CXCR4 antagonists have been developed to block SDF-1/CXCR4 interactions that are currently under different stages of development. The first in class CXCR4 antagonist, plerixafor, was approved by the FDA in 2008 for the mobilization of hematopoietic stem cells and several other drugs are currently in clinical trials for cancer, HIV, and WHIM syndrome. While the long-term safety data for the first generation CXCR4 antagonists are not yet available, several new compounds are under preclinical development in an attempt to provide safer and more efficient treatment options for HIV and cancer patients.

Synthesis of β-amino-α-trifluoromethyl alcohols and their applications in organic synthesis

A comprehensive overview on methods applied for syntheses of β-amino-α-trifluoromethyl alcohols, including stereocontrolled variants, is presented. In addition, reported cases of the exploration of β-amino-α-trifluoromethyl alcohols for the preparation of trifluoromethylated peptidomimetics and other biologically active, fluorinated compounds are discussed. Attractive opportunities for their applications as organocatalysts are also presented.

Synthesis and biological evaluation of selective CXCR4 antagonists containing alkene dipeptide isosteres

A set of cyclic peptide analogues of a selective CXCR4 antagonist FC131 [cyclo(-d-Tyr-Arg-Arg-Nal-Gly-)] were synthesized and bioevaluated. Using (E)-alkene and (Z)-fluoroalkene dipeptide isosteres for Arg-Arg and Arg-Nal substructures, indispensable or the partial contribution of the two peptide bonds to the CXCR4 antagonism and anti-HIV activity was demonstrated. FC131 and the analogues were shown to selectively inhibit SDF-1 binding to CXCR4, whereas no inhibition of binding of SDF-1 to CXCR7 was observed.