ortho-Lithiation Reactions of O-(3,n-Dihalophenyl) N,N-Diethylcarbamates: Synthesis of Dihalosalicylamides and 2,3,n-Trihalophenol Derivatives

New dihalosalicylamides and trihalophenol derivatives have been synthesized from easily available O-(3,n-dihalophenyl) N,N-diethylcarbamates by using a directed ortho-metalation (DoM) strategy. The o-lithiation reactions with sBuLi take place regioselectively at the doubly activated C-2 position, which demonstrates the ability of O-carbamates as directed metalating groups. In addition, highly functionalized arylnitriles were accessed from organolithium intermediates by using a tandem transnitrilation/SNAr reaction sequence.Junta de Castilla y León (Consejería de Educación) and FEDER (BU237U13 and BU076U16) as well as the Ministerio de Economía y Competitividad (MINECO) and FEDER (CTQ2013-48937-C2-1-P

Modular construction of fluoroarenes from a new difluorinated building block via cross-coupling/electrocyclisation/ dehydrofluorination reactions

Palladium-catalysed coupling reactions based on a novel and easy-to-synthesise difluorinated organotrifluoroborate were used to assemble precursors to 6π-electrocyclisations of three different types. Electrocyclisations took place at temperatures between 90 and 240 oC, depending on the central component of the π-system; non-aromatic trienes were most reactive, but even systems which required the temporary dearomatisation of two arenyl sub-units underwent electrocyclisation, albeit at elevated temperatures. Photochemical conditions were effective for these more demanding reactions. The package of methods delivered a structurally-diverse set of fluorinated arenes, spanning a 20 kcal mol-1 range of reactivity, by a flexible route