Chromatography-Free Allylic Cleavage

Significance

A chromatography-free workup protocol for cleavage of allylalkyl ethers yielding the parent alkyl alcohols was developed. The palladium-catalyzed allylic Suzuki coupling of the allylalkyl ether was carried out with vinylboronic anhydride-pyridine complex in the presence of a catalytic amount of Pd(OAc)₂ and 4-(diphenyl­phosphino)benzoic acid to give the desired parent alcohol and the volatile co-products. The crude reaction mixture was treated with polystyrene-bound diethanolamine (PS-DEAM) where the boronic ester underwent alcoholysis and the resulting boronic acid was scavenged by PS-DEAM. At the same workup step, the acidic phosphine (and/or phoshine oxide) and the palladium residue were trapped by PS-DEAM. The mixture was filtered and the filtrate was concentrated in vacuo to give the desired parent alcohol.