Synthesis of E-Dienyl Esters Using Acetylene as C2 Synthon.

The stereoselective synthesis of dienyl esters with high atom- and step-economy has been largely unexplored. Herein, we report an efficient approach for the synthesis of E-dienyl esters via rhodium catalysis using carboxylic acid and acetylene as C2 synthon through the cascade of cyclometalation and C-O coupling. This protocol features mild conditions, excellent functional group tolerance, and exclusive E-stereoselectivity and utility in the late-stage modification of pharmaceuticals and natural products.

Cu-catalyzed carboboration of acetylene with Michael acceptors.

A copper-catalyzed three-component carboboration of acetylene with B2Pin2 and Michael acceptors is reported. In this reaction, a cheap and abundant C2 chemical feedstock, acetylene, was used as a starting material to afford cis-alkenyl boronates bearing a homoallylic carbonyl group. The reaction was robust and could be reliably performed on the molar scale. Furthermore, the resulting cis-alkenyl boronates could be converted to diverse functionalized molecules with ease.

Construction of Partially Protected Nonsymmetrical Biaryldiols via Semipinacol Rearrangement of o-NQM Derived from Enynones.

The construction of partially protected nonsymmetrical biaryldiols catalyzed by AgBF4 has been achieved. The approach facilitates the formation of two new aryl rings and the introduction of two hydroxyl groups (one free and one TBS-protected) via the o-NQM generation/semipinacol rearrangement cascade, featuring high atom- and step-economy to afford a diverse array of partially protected nonsymmetrical biaryldiols under mild conditions.