The synthesis of 2-benzazocines using ring-closing metathesis as a key step

A number of protected 7-isopropoxy-8-methoxy-1,2,3,6-tetrahydro-2-benzazocines were synthesized from 2-allyl-3-isopropoxy-4-methoxybenzaldehyde using ring-closing metathesis as the key step. In addition, two 9-isopropoxy-8-methoxy-3,6-dihydro-2-benzazocines were synthesized from 5-isopropoxy-4-methoxy-2-[(1E)-3-phenyl-2-propenyl]benzaldehyde, which in turn was obtained from the thermal Claisen–Cope rearrangement of 4-methoxy-3-{[(2E)-3-phenyl-2-propenyl]oxy}benzaldehyde. Finally, five of the 2-benzazocine compounds were tested for anti-cancer activity.

Graphical abstractA number of substituted 2-benzazocines were synthesized from 2-allyl-3-isopropoxy-4-methoxybenzaldehyde and 5-isopropoxy-4-methoxy-2-[(1E)-3-phenyl-2-propenyl]benzaldehyde using ring-closing metathesis as the key step.Figure optionsDownload full-size imageDownload as PowerPoint slide