The free C2-position of DTS core in compound 5 was subsequently converted to their corresponding carbaldehydes 6 by performing the Vilsmeier-Haack reaction, affording 6a and 6b in 64% and 78% yield, respectively
The free C2-positionof DTS core in compound 5 was subsequently converted totheir corresponding carbaldehydes 6 by performing theVilsmeier-Haack reaction, affording 6a and 6b in 64%and 78% yield, respectively