Synthesis of allyltrifluoroborates
Allyl alcohols were regio- and stereoselectively converted to allyl boronic acids and subsequently to trifluoro(allyl)borates with tetrahydroxy diboron with high isolated yields using palladium pincer-complex catalysis. A mechanism for the fast allylic displacement of a hydroxy group is discussed.
V. J. Olsson, S. Sebelius, N. Selander, K. J. Szabó, J. Am. Chem. Soc., 2006, 128, 4588-4589.
A mild, selective, palladium-catalyzed boronation of vinyl cyclopropane, vinyl aziridine, and allyl acetate substrates could be accomplished using tetrahydroxydiboron in the presence of a palladium pincer complex catalyst to give synthetically useful linear trifluoro(allyl)borates or allyl boronates incorporating a trans double bond. Functionalities such as Br, COOEt, ArSO2(NH), OAc, and SiRMe2 are tolerated.
S. Sebelius, V. J. Olsson, K. J. Szabó, J. Am. Chem. Soc., 2005, 127, 10478-10479.
3-Substituted-2-alkoxycarbonyl allylboronates are readily produced by the cross-coupling of Baylis-Hillman acetate adducts and bis(pinacolato)diboron in the presence of a palladium catalyst. Subsequent addition of excess aqueous KHF2 gives stable allyl trifluoroborate salts. Allylboronate and allyltrifluoroborate derivatives react stereoselectively with aldehydes to afford functionalized homoallylic alcohols.
G. W. Kabalka B. Venkataiah, G. Dong, J. Org. Chem., 2004, 69, 5807-5809.