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A base-mediated (3 + 2) cycloaddition of trifluoroacetohydrazonoyl chlorides with imidates for the construction of 3-trifluoromethyl-1,2,4-triazoles has been described. This reaction is characterized by readily starting materials, simple reaction conditions, good yields, a broad substrate scope, and excellent regioselectivity. The utility of this protocol has been validated by the synthesis of a drug-like molecule.

We report a general and efficient approach to construct achiral and chiral gem -difluoroallylic amines from a masked difluorodiazo reagent (PhSO 2 CF 2 CHN 2 ) and readily available imines. This facile protocol takes advantage of the phenylsulfonyl and diazo moieties as efficient activating and directing groups to assist difluoroalkyl incorporation and facilitate the chemodivergent and stereoselective formation of gem -difluoroallylic amines.

A silver-catalyzed regioselective [3 + 2] cycloaddition reaction of PhSO 2 CF 2 CHN 2 with aryl diazonium salts is described. This protocol enables the straightforward construction of a novel class of difluoromethylated tetrazoles under mild conditions, tolerates a broad spectrum of functionalities, and is applicable to one-pot operation from commercially available aniline derivatives. The synthetic merit of this method is further demonstrated by the facile preparation of versatile difluoromethylated azoles, including a valuable HCF 2 -analogue of P2X3 receptor antagonist.

Phenylsulfone difluorodiazoethane (PhSO 2 CF 2 CHN 2 ), an easy-to-prepare and bench-stable masked CF 2 -building block, has been developed. The synthetic utility of this reagent is demonstrated by a direct regioselective [3 + 2] cycloaddition with electron-deficient alkynes and alkenes. This protocol enables facile construction of an array of difluoromethyl-substituted pyrazoles in good to high yields under mild reaction conditions.

A telescoping process involving the consecutive addition of four reagents (trifluorodiazoethane, phosphine, allenyl ester, and acetic acid) into a single reactor was developed for the novel functionalization of allenyl esters. First, new phosphazenes derived from trifluorodiazoethane and phosphines were generated and reacted with allenyl esters to give unexpected α-iminophosphoranes through the creation of C=P, C=N, and C-H bonds at the α-, β-, and γ-carbon atoms, respectively, of the allenyl esters. The α-iminophosphoranes did not react with aldehydes in a classic Wittig reaction, but instead β-enamino esters were obtained. The overall sequence of reactions offered a formal hydrohydrazonation of allenyl esters. The method was extended to other related diazo compounds and applied to the preparation of novel 5-pyrazolone derivatives. Not only is the telescoping process described herein an effective approach for truncating the multistep synthesis, but also each step has been dissected to understand and support the reaction mechanisms., (© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

An organocatalytic asymmetric decarboxylative amination reaction of β-keto acids is described. Under mild reaction conditions, a series of chiral α-amino ketones were obtained in good to high yields (up to 99%) and enantioselectivities (up to 95% ee). A chiral 1,2-amino alcohol was synthesized from the corresponding decarboxylative amination product in several steps without loss of enantioselectivity.

The regio- and stereoselective ring opening of 1,2- and 1,3-sulfamidates with trifluoromethanethiolate anion is reported. This direct introduction of the whole SCF 3 motif is a straightforward synthetic route toward β- and γ-SCF 3 amines and α-amino acid derivatives. The utility of this reaction was further illustrated by incorporation of Cys(S-CF 3 ) into di- and tripeptides.

A simple C 2 -symmetric chiral bisoxazoline is demonstrated to use hydrogen bonding to catalyze an important family of aldol reactions of trifluoroacetaldehyde hemiacetals with various β-carbonyl acids. This reaction is highly enantioselective, delivering chiral nonracemic trifluoromethylated alcohols with excellent optical purity and good isolated yields. This concept of relaying chiral information via a chiral hydrogen-bond acceptor should be applicable to a vast number of organocatalytic processes.

The increasing availability of highly active no-carrier-added [(18)F]-fluoride makes its use in radiolabeling biomolecules attractive. By incorporating "fluorophilic" elements (Si, B, and Al) into biomolecules, recent advances offer mild and rapid (18)F-labeling approaches without HPLC purification at the radiosynthetic stage while maintaining sufficient specific activity. In this Topical Review, we will discuss the most recent strides in the field.

A novel copper-catalyzed one-pot cross-coupling of β-ketoacids with in situ generated trifluorodiazoethane has been developed. This reaction provides a direct and efficient method, in which one C-C bond and one C-O bond were formed in a carbenoid center with concomitant denitrogenation-dehydrogenation-decarboxylation, to afford trifluoromethylated aldol products. In several preliminary experiments, good to high enantioselectivities were also obtained., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)