Assignment of absolute configuration of 8α-hydroxy-13-hydroperoxylabd-14,17-dien-19,16;23,6α-diolide by computed NMR chemical shifts.

ABSTRACT

Unassigned configurations of 8α-hydroxy-13-hydroperoxylabd-14,17-dien-19,16;23,6α-diolide, extracted from Iranian salvia, in the C13 and C16 were assigned as S and R, respectively. Extensive ab initio calculations followed by chemical shift predictions were employed in this assignment. Predicted chemical shifts were correlated to experimental ones in order to find the correct configuration, shown here.