Benzynes were generated from o-(trimethylsilyl)phenols using nonafluorobutanesulfonyl fluoride (NfF) by a domino process, i.e., the nonaflation of the phenolic hydroxyl group of o-(trimethylsilyl)phenols by NfF followed by the attack of the produced fluoride ion on the trimethylsilyl group. The generated benzyne immediately underwent various reactions to give polysubstituted benzenes.

Nucleophilic deoxyfluorinaiton of one of the two hydroxyl groups of catechols has been developed via the Umpolung concept. This method was successively applied to naturally occurring catechols, such as catechins and dopamine, to produce novel fluorinated analogues.

Cause and effect: The first ortho‐selective nucleophilic addition reaction of amines to 3‐substituted benzynes has been achieved. Despite a large trimethylsilyl substituent, primary amines attack the C2 position of 3‐silylbenzynes to produce 2‐silylanilines (see scheme). This outcome is likely to result from the inductive electron‐donating effect of the silyl group, which overrides its steric repulsion with the approaching amines.

The fluorination of substituted benzenes using fluoride ions under mild reaction conditions has been one of the most important challenges for the synthesis of biologically active fluorinated aromatic compounds; however, only a few synthetically useful methods are known. In this paper, it is reported that the nucleophilic fluorination of benzynes, generated from either 2-(trialkylsilyl)phenyl nonafluorobutanesulfonates or 2-(trialkylsilyl)phenols, meets this challenge. In particular, the fluorination starting from 2-(trialkylsilyl)phenols for fabricating aryl fluorides involves three sequential reactions in one-pot: the nonaflylation of phenols, benzyne generation, and nucleophilic fluorination of the benzynes. The regioselectivities of these reactions are controlled by the substituents at the C3-position of the benzynes.

Ursache und Wirkung: Bei der Titelreaktion greifen primäre Amine trotz eines großen Trimethylsilyl‐Substituenten die C2‐Position von 3‐Silylbenz‐inen unter Bildung von 2‐Silylanilinen an (siehe Schema). Dieser Reaktionsverlauf resultiert wahrscheinlich aus dem induktiven elektronenschiebenden Effekt der Silylgruppe, der gegenüber ihrer sterischen Abstoßung angreifender Amine überwiegt.