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Chirality Transfer in Gold(I)‐Catalysed Direct Allylic Etherifications of Unactivated Alcohols: Experimental and Computational Study
Author(s) -
Barker Graeme,
Johnson David G.,
Young Paul C.,
Macgregor Stuart A.,
Lee AiLan
Publication year - 2015
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201501607
Subject(s) - chirality (physics) , allylic rearrangement , chemistry , nucleophile , regioselectivity , substituent , axial chirality , computational chemistry , stereoselectivity , stereochemistry , enantioselective synthesis , catalysis , organic chemistry , physics , chiral symmetry breaking , symmetry breaking , quantum mechanics , nambu–jona lasinio model
Gold(I)‐catalysed direct allylic etherifications have been successfully carried out with chirality transfer to yield enantioenriched, γ‐substituted secondary allylic ethers. Our investigations include a full substrate‐scope screen to ascertain substituent effects on the regioselectivity, stereoselectivity and efficiency of chirality transfer, as well as control experiments to elucidate the mechanistic subtleties of the chirality‐transfer process. Crucially, addition of molecular sieves was found to be necessary to ensure efficient and general chirality transfer. Computational studies suggest that the efficiency of chirality transfer is linked to the aggregation of the alcohol nucleophile around the reactive π‐bound Au–allylic ether complex. With a single alcohol nucleophile, a high degree of chirality transfer is predicted. However, if three alcohols are present, alternative proton transfer chain mechanisms that erode the efficiency of chirality transfer become competitive.