Skeletal Diversification via Heteroatom Linkage Control: Preparation of Bicyclic and Spirocyclic Scaffolds from N‑Substituted Homopropargyl Alcohols

The discovery and application of
a new branching pathway synthesis
strategy that rapidly produces skeletally diverse scaffolds is described.
Two different scaffold types, one a bicyclic iodo-vinylidene tertiary
amine/tertiary alcohol and the other, a spirocyclic 3-furanone, are
each obtained using a two-step sequence featuring a common first step.
Both scaffold types lead to intermediates that can be orthogonally
diversified using the same final components. One of the scaffold types
was obtained in sufficiently high yield that it was immediately used
to produce a 97-compound library.