Application of lithium n -Butylselenolate in the Total Syntheses of (+)-Pericosine B, (+)-Pericosine C, (+)-COTC and 7-Chloro-analogue of (+)-Gabosine C

Carbasugars are important carbohydrate analogs in which the ring oxygen is replaced with a methylene group. This change has no significant impact on structure (bonds length, torsion angles, conformation) but strongly affects biological activity (pharmacokinetics, molecule-enzyme interactions).1 The therapeutic potential of some carbasugars has led to a growing interest in their development and identification. In our work, we present our recent studies of the application of the tandem seleno-Michael/aldol process in carbasugar synthesis involving D-ribose as a readily available and cheap starting material. An intramolecular seleno-Michael/aldol reaction turned out to be a key step in the asymmetric synthesis of the carbasugar core. In situ generated lithium n-butylselenolate was used as the initiator in the reaction.2,3 Regioselective Steglich esterification or methylation of the secondary hydroxyl and deprotection of benzyl ethers groups gave three known carbasugars (+)-COTC, (+)-Pericosine B and (+)-Pericosine C and a new 7-chloro-analogue of (+)-Gabosine C in satisfactory yields.3 This work was financed by the Polish National Science Center: Grant No. 2015/17/D/ST5/01334 [1] O. Arjona, A.M. Gomez, J.C. Lopez, J. Plumet, Chem. Rev. 107 (2007) 1919-2036 [2] P. Banachowicz; J. Mlynarski ; S.Buda , J. Org. Chem., 2018, 83, 11269-11277. [3] N. Biduś; P. Banachowicz; S. Buda, Tetrahedron, 2020, doi.org/10.1016/j.tet.2020.131397.