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)
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Highly chemoselective conjugate addition of lithium tetraorganozincates to2
coumarin derivatives and functionalization with electrophiles3
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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
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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.