Categories: C-C Bond Formation > Chains >
Benzylic Substitutions, Benzylation
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Recent Literature
An enantioselective nickel-catalyzed Negishi cross-coupling of racemic
secondary benzylic bromides and chlorides is described. The catalyst
components are commercially available and air-stable, and the reaction is
not highly oxygen- or moisture-sensitive.
F. O. Arp, G. C. Fu, J. Am. Chem. Soc.,
2005,
127, 10482-10483.
An insoluble, amphiphilic and polymeric palladium catalyst (PdAS) is an excellent catalyst for the
Suzuki-Miyaura reaction. The catalyst is reusable after easy work up and showed
good stability in any reaction medium.
Y. M. A. Yamada, K. Takeda, H. Takashashi, S. Ikegami, J. Org. Chem.,
2003,
68, 7733-7741.
An enhanced Lewis acid system of InCl3 and Me3SiBr can be used to promote a
wide range of direct coupling reactions between alcohols and silyl nucleophiles
in non-halogenated solvents. Highly chemoselective allylations toward a hydroxyl
moiety over ketone and acetoxy ones have been demonstrated.
T. Saito, Y. Nishimoto, M. Yasuda, A. Baba, J. Org. Chem., 2006,
71, 8516-8522.
The reaction of alkoxides with boron trichloride results in the generation
of cations that can be allylated in subsequent transformations. The absence
of Brønsted acids can make a significant difference in such syntheses.
G. W. Kabalka, M.-L. Yao, S. Borella, J. Am. Chem. Soc., 2006,
128, 11320-11321.
An efficient protocol for the palladium-catalyzed Heck alkynylation using XPhos
as ligand and Cs2CO3 as the base, couples a wide range of
functionalized terminal alkynes and substituted benzyl chlorides. An excess
amount of base and higher reaction temperatures allows the synthesis of allenes
in a one-pot procedure.
C. H. Larsen, K. W. Anderson, R. E. Tundel, S. L. Buchwald, Synlett, 2006,
2941-2946.
The reaction of alkynylboron dihalides with benzylic, allylic, and
propargylic alcohols provides an efficient route to internal acetylenes
without isomerization of the product alkynes under the reaction conditions.
G. W. Kabalka, M.-L. Yao, S. Borella, Org. Lett.,
2006,
8, 879-881.
