Toward synthesis of carbasugars (+)-gabosine C, (+)-COTC, (+)-pericosine B, and (+)-pericosine C.

Asymmetric total synthesis of (+)-gabosine C, (+)-pericosine B, and (+)-pericosine C has been reported from readily available d-(-)-isoascorbic acid and d-ribose involving Grubbs ring closing metathesis, Morita-Baylis-Hillman (MBH) reaction, and Luche reduction.