6738-12-1Relevant articles and documents
First direct synthesis of 3-hydroxy-pent-4-ynoic acids. Application to the synthesis of pyran-2-ones
López-Reyes, Morelia E.,López-Cortés, José G.,Ortega-Alfaro, M. Carmen,Toscano, R. Alfredo,Alvarez-Toledano, Cecilio
, p. 7365 - 7372 (2013/08/23)
We describe a direct method for the synthesis of 3-hydroxy-pent-4-ynoic acids by the nucleophilic addition of bis-(TMS) ketene acetals to alkynones promoted by BF3·Et2O. A systematic study involving electron withdrawing and electron donor groups (R1=NO2, CF3, Br, Cl, H, Me, OMe) in the propargyl ketone reveals a strong dependence of electronic effects on the regiochemistry of the nucleophilic addition. Using a halolactonization protocol, we demonstrated the synthetic potential of these acids by their efficient transformation into new 5-bromo-3,4-dihydro-2H-pyran-2-ones.