Polycyclic compounds by Ugi-Pictet-Spengler sequence.

A general approach to architecturally stimulating polycyclic structures is described by a concise, two-step procedure including a Ugi MCR (multicomponent reaction) and a subsequent Pictet-Spengler reaction starting from phenylethylamine-derived isocyanides. Ten compounds are described in full experimental detail, and yields range from medium to very good. Some of the reactions run with a high degree of stereoselectivity. The compound structures resemble steroid hormones and alkaloid classes of natural products. Exemplary products have been fully reduced to their tertiary amines. As such they could potentially become interesting biological probes.