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Highly Enantio‐ and Regioselective Allylic Alkylations Catalyzed by Chiral [Bis(dihydrooxazole)]molybdenum Complexes
Author(s) -
Glorius Frank,
Neuburger Markus,
Pfaltz Andreas
Publication year - 2001
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/1522-2675(20011017)84:10<3178::aid-hlca3178>3.0.co;2-q
Subject(s) - chemistry , tsuji–trost reaction , allylic rearrangement , regioselectivity , enantioselective synthesis , molybdenum , enantiomer , pyridine , stereochemistry , ligand (biochemistry) , medicinal chemistry , catalysis , alkylation , organic chemistry , receptor , biochemistry
A series of chiral C 2 ‐symmetric bis[dihydrooxazoles] with a trans ‐1,2‐diaminocyclohexane backbone was synthesized. In view of the promising results obtained by Trost et al. with related bis[pyridine] ligands, we tested these new ligands in the enantioselective molybdenum‐catalyzed allylic alkylation of 1‐ and 3‐monosubstituted allylic substrates. Enantiomer excesses of up to 98% and branched/linear ratios of up to 11 : 1 were obtained with ( E )‐3‐(alkyl)allyl carbonates. ( E )‐3‐Phenoxyallyl acetate gave a branched/linear ratio of >20 : 1 and an ee of 98%. Crystal structures of the free ligand 7a and of its tricarbonylmolybdenum(0) complex 28 are reported.