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

•Key intermediate 9 was prepared from d-(−)-isoascorbic acid as well as d-ribose.•Bio-active compounds 1, 4, and 5 were obtained from a common intermediate 18.•Grubbs RCM, Morita–Baylis–Hillman (MBH), and Luche reductions are key steps. 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.