Synthesis and Isolation of Organogold Complexes through a Controlled 1,2-Silyl Migration

During our efforts toward the synthesis of naturally occurring polyprenylated polycyclic acylphloroglucinol using a Au(I)-catalyzed 6-endo dig carbocyclization, we isolated stable vinyllic gold intermediates. Optimization lead to isolated yields of up to 98%, using 2-(di-tert-butylphosphino)biphenyl as the ligand. This transformation is derived from a silyl rearrangement that can be fully controlled according to the nature of the substituent on the ynone. This selective transformation does not require basic conditions to prevent protodeauration. These vinylgold complexes are the first isolated intermediates during a silyl migration with gold(I). More than 16 new organogold complexes were synthesized and characterized by single-crystal X-ray diffraction. Reactivity of these complexes is also presented.