This review covers recent advances in C-H bromination of aromatic substrates. Transition-metal-catalyzed/-mediated reactions and transition-metal-free methods are discussed.

No abstract

1-(Propargyl)indol-2-carbonitriles react with alcohols to afford 1-alkoxypyrazino[1,2- a]indoles under DBU-catalyzed microwave-assisted conditions. The reaction scope includes a wide range of indoles, primary and secondary alcohols, and a thiol. The initial mechanistic study shows that the domino process presumably proceeds through an alkyne-allene rearrangement, imidate formation, and nucleophilic cyclization reaction sequence.

The reaction of 1,2-disubstituted 2-imidazolines with electron-deficient alkynes proceeds as a pseudo-threecomponent process and forms imidazolidines with an N-vinylpropargylamine fragment. Heating the resulting imidazolidines in xylene on air leads to an effective formation of polysubstituted pyrroles through a domino sequence of aza-Claisen rearrangement/ transannular nucleophilic addition/oxidative ring opening reactions. The direct one-pot transformation of 2-imidazolines to pyrroles has been also realized.

Methods for the design of nitrogen-containing heterocyclic systems involving the formation of C-N bonds under the conditions of the Mitsunobu reaction are discussed.The Mitsunobu reaction [1][2][3][4] is the reaction of compounds containing a mobile hydrogen atom HX with alcohols in the presence of a reagent system consisting of an azodicarboxylic ester and a phosphine PR 1 3 . This reaction results in the formation of an alkylation product RX accompanied by oxidation of the phosphine PR 1 3 to phosphine oxide R 1 3 P=O and reduction of the azodicarboxylic ester to the corresponding hydrazine.The reaction takes place under very mild conditions and usually at room temperature. If a chiral secondary alcohol ROH is used, the reaction is usually stereospecific and is accompanied by inversion of the configuration at the asymmetric carbon atom of the alcohol [1-3].From the moment of the first report [5] the Mitsunobu reaction became a powerful tool in synthetic organic chemistry and found widespread use in the synthesis of various heterocyclic compounds, optically active substances, steroids, alkaloids, carbohydrates, and nucleosides [1][2][3][4]6]. In particular, in a number of cases the Mitsunobu reaction has made it possible to synthesize new physiologically active compounds or to put forward new highly effective approaches to synthesis. Several reviews have been devoted to the Mitsunobu reaction [1-4, 6, 7]. Data on the use of the Mitsunobu reaction in the synthesis of alkaloids were reviewed in [6]. Various experimental techniques that make it possible to simplify the isolation of the products of the Mitsunobu reaction RX from the reaction mixture, including the use of reagents attached to a polymer support, were discussed in [7]. _______ * Dedicated to Afanasi Andreevich Akhrem on his 95th birthday. _________________________________________________________________________________________