A Convergent Synthesis of (+)‐Parviflorin, (+)‐Squamocin K, and (+)‐5S‐Hydroxyparviflorin

Thirty of the thirty-five carbon atoms of the acetogenin (+)-parviflorin (3, also named squamocin E) in this highly convergent synthesis derive from one building block, the readily accessible alcohol 1. The remaining five have their origin in an alkyne obtained from lactic acid. The key step of this general strategy to bis(tetrahydrofuran) acetogenins is a Ru-catalyzed Alder–ene coupling of the alkyne with a bis(tetrahydrofuran) made from two units of 1.