Tandem Diene Diborylation Silaboration Allylboration

Miyaura and co-workers have developed a one-pot borylation/allylation tandem process based on the borylation of various ketone-containing allylic acetates [139]. 

The intramolecular allylboration step was very slow in DMSO, which is the usual solvent for these borylations of allylic acetates (Section 6.2.1.6). Alternatively, a non-co-ordinating solvent like toluene was more suitable for the overall process, provided an arsine or phosphine ligand is added to stabilize the active Pd(0) species during the borylation. With cyclic ketones such as 109 the intramolecular allylation provided cis-fused bicyclic products (110), in agreement with the involvement of the usual chairlike transition state (Equation 55). An intermolecular tandem borylation/allylation was also reported [59]. 

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