Core skeleton: a seven-membered heterocycle (oxepine, i.e. one oxygen and six carbons in the ring).  Number the ring beginning with the hetero-oxygen as position 1 and proceed clockwise (1 to 7).  Ring unsaturation is alternating: C2=C3, C4=C5 and C6=C7 are double bonds; the remaining ring bonds (O1-C2, C3-C4, C5-C6, and C7-O1) are single.

Substituents on this ring:
- C2 bears a pinacol boronate group, specifically a five-membered dioxaborolane ring (B-O-C-C-O- back to B), in which each of the two carbons in the ring is quaternary and carries two methyl groups.
- C5 is substituted with a benzene ring.

No other substituents or stereochemical features are present.