Catalytic transient leaving group for atom-economic synthesis of allenes from 2-alkynolsElectronic supplementary information (ESI) available. See DOI: 10.1039/c7cc06866b

An atom economic approach from readily available propargylic alcohols to allenes, the first carboxylation of propargylic alcohols, has been established. Through the cooperative binary catalysis of Pd and a phosphoric acid, the reaction afforded multi-substituted allenoates with a broad scope tolerating useful functional groups. The synthetic potential of the obtained products has been demonstrated. An atom economic approach to multi-substituted allenes from propargylic alcohols with water as the only byproduct has been established.