Alkylation and silylation of α-fluorobenzyl anion intermediates.

Simple α-fluorobenzyl anions reacted with electrophiles such as non-activated alkyl halides and chlorotrimethylsilane. Upon treatment with LTMP as the base, fluoromethylbenzenes took part in the formation of α-monofluorobenzyl anions without stabilizing -substituents. Furthermore, the resulting α-silyl fluoromethylbenzenes reacted with electrophiles such as acetophenone and benzaldehyde in the presence of cesium fluoride to form α-fluorobenzylated alcohols.

Synthesis of 3-fluoro-2,5-disubstituted furans through ring expansion of gem-difluorocyclopropyl ketones.

The synthesis of 3-fluoro-2,5-disubstituted furans from gem-difluorocyclopropyl ketones was accomplished using trifluoromethanesulfonic acid (CFSOH) through ring expansion owing to the activation of the carbonyl group in the starting material. The present synthesis of 3-fluorofurans tolerates substrates designed for products with aromatic substituents at the C-2 and C-5 positions.

Carbon-carbon bond cleavage for Cu-mediated aromatic trifluoromethylations and pentafluoroethylations.

This short review highlights the copper-mediated fluoroalkylation using perfluoroalkylated carboxylic acid derivatives. Carbon-carbon bond cleavage of perfluoroalkylated carboxylic acid derivatives takes place in fluoroalkylation reactions at high temperature (150-200 °C) or under basic conditions to generate fluoroalkyl anion sources for the formation of fluoroalkylcopper species. The fluoroalkylation reactions, which proceed through decarboxylation or tetrahedral intermediates, are useful protocols for the synthesis of fluoroalkylated aromatics.

Zinc(II)-catalyzed redox cross-dehydrogenative coupling of propargylic amines and terminal alkynes for synthesis of N-tethered 1,6-enynes.

The zinc(II)-catalyzed redox cross-dehydrogenative coupling (CDC) of propargylic amines and terminal alkynes proceeds to afford N-tethered 1,6-enynes. In the current CDC reaction, a C(sp)-C(sp(3)) bond is formed between the carbon adjacent to the nitrogen atom in the propargylic amine and the terminal carbon of the alkyne with reduction of the C-C triple bond of the propargylic amine, which acts as an internal oxidant.

Copper(I)-catalyzed substitution reactions of propargylic amines: importance of C(sp)-C(sp3) bond cleavage in generation of iminium intermediates.

Substitution reactions of propargylic amines proceed in the presence of copper(I) catalysts. Mechanistic studies showed that C(sp)-C(sp(3)) bond cleavage assisted by nitrogen lone-pair electrons is essential for the reaction, and the resulting iminium intermediates undergo amine exchange, aldehyde exchange, and alkyne addition reactions. Because iminium intermediates are key to aldehyde-alkyne-amine (A(3)) coupling reactions, this transformation is effective not only for reconstruction of propargylic amines but also for chiral induction of racemic compounds in the presence of chiral catalysts.