Rh(I)‐Catalyzed Decarboxylative Arylation of Alkynyl Cyclic Carbonates: Divergent Access to Substituted α‐Allenols and 1,3‐Butadienes

Rh(I)‐catalyzed decarboxylative arylation of alkynyl cyclic carbonates using commercially available and low‐toxic aryl boronic acids has been disclosed. Depending on the nature of the cyclic carbonates, the methodology provides a straightforward platform to access either substituted 2,3‐allenols or 1,3‐butadiene derivatives. Internal alkynyl cyclic carbonates undergo monoarylation to conveniently afford 2,3‐allenols with high syn‐selectivity for the aryl and hydroxy groups. Whereas, terminal alkynyl carbonates led to the formation of diarylated 1,3‐butadiene derivatives having cis‐configuration for the two aryl groups via allenyl rhodium(I)alkoxide intermediate. The compatibility of various functional groups allowed to develop a library of diversely functionalized scaffolds with excellent regioselectivity in good yields. Late‐stage transformation of a series of natural products highlights the wide applicability of the arylation process. Additionally, scale‐up experiments and downstream transformations of α‐allenol derivatives into other valuable heterocycles illustrate the efficacy of the protocol.