Planar Chiral Pseudo‐Isocoumarins by Copper Catalysed Desymmetrisation.

A new copper catalysed desymmetrisation reaction of bisalkynyl ferrocenecarboxylic acids using (R,R)‐Ph‐Pybox results in the first asymmetric synthesis of planar chiral pseudo‐isocoumarins in up to 64 % enantiomeric excess and up to 99 % yield with complete regioselectivity. Tri‐functionalised planar chiral ferrocenes are synthesised in five steps from commercially available materials, without the need for traditional directing group chemistry via an easily diversified route exploiting the double Sonogashira coupling reaction. The absolute configuration of the chiral heterocycles is proven by chemical correlation and circular dichroism spectroscopy giving the asymmetric reaction synthetic utility and opening the way for the rational extension of this method to produce bioactive isocoumarin‐fused ferrocene derivatives. [ABSTRACT FROM AUTHOR]