Highly chemoselective conjugate addition of lithium tetraorganozincates to coumarin derivatives and functionalization with electrophiles

DOI: https://doi.org/10.24820/ark.5550190.p011.877 Page 1 ©AUTHOR(S) A Platinum Open Access Journal for Organic Chemistry Paper Free to Authors and Readers DOAJ Seal Arkivoc 2023, part iii, 0-0 to be inserted by editorial office 1 Highly chemoselective conjugate addition of lithium tetraorganozincates to2 coumarin derivatives and functionalization with electrophiles3 4 Marzia Dell'Aera,a,b Filippo Maria Perna,b Paola Vitale,b Antonio Salomone,c5 Angela Altomare,a and Vito Capriati*b6 7 a Istituto di Cristallografia (IC-CNR), Via G. Amendola 122/o, 70125 Bari, Italy8 b Dipartimento di Farmacia-Scienze del Farmaco, Università degli Studi di Bari "Aldo Moro", Consorzio9 C.I.N.M.P.I.S., Via E. Orabona 4, 70125, Bari, Italy10 c Dipartimento di Chimica, Università degli Studi di Bari "Aldo Moro", Consorzio C.I.N.M.P.I.S., Via E. Orabona 4,11 70125, Bari, Italy12 Email: vito.capriati@uniba.it13 14 Dedicated to Professor Saverio Florio for his contribution to synthetic organic chemistry15 Received mm-dd-yyyy Accepted Manuscript mm-dd-yyyy Published on line mm-dd-yyyy16 Dates to be inserted by editorial office17 Abstract18 The nucleophilic addition (alkylation/arylation) of lithium tetraorganozincate species (R4ZnLi2) to coumarin19 derivatives takes place cleanly, with a short reaction time (30 min) and with high chemoselectivity, when20 working under mild conditions (0 °C) and with no additional solvents. Particularly remarkable is the21 diastereoselectivity of the reaction (up to 96:4), after trapping the resulting intermediates with external22 electrophiles. The stereochemistry of the major trisubstituted stereoisomer was assigned by combining 2D23 NOESY experiments with DFT calculations.