Catalytic compositions and methods for asymmetric allylic alkylation
AssigneeThe Board of Trustees of the Leland Stanford Junior University
InventorsBarry M. Trost, Iwao Hachiya
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Abstract
Complexes of a selected class of chiral ligands with molybdenum, tungsten or chromium, preferably molybdenum, are effective as catalysts in highly enantioselective and regioselective alkylation of allylic substrates.
Claims25
A catalytic organometallic composition, effective to catalyze the enantioselective alkylation of an allyl group bearing a leaving group at an allylic position, said composition comprising:
- a metal atom selected from the group consisting of molybdenum, tungsten, and chromium, and coordinated thereto, a chiral ligand L1 comprising:
- a chiral component derived from a chiral diamine, said component comprising first and second carbon atoms, each bearing a binding group —NH—(C═O)—B, wherein
- said carbon atoms are connected by a direct bond or by a chain of one to three atoms comprising linkages selected from alkyl, alkyl ether, alkyl amino, and combinations thereof;
- each group B is independently selected from alkyl, cycloalkyl, heterocycle, aryl, and aralkyl;
- at least one group B is a N-heterocyclic or N-heteroaryl group CyN having an sp2 hybridized ring nitrogen atom effective to coordinate to said metal atom;
- and
- at least one of said carbon atoms is a chiral carbon atom bearing a further substituent, wherein said substituent or substituents are independently selected from aryl, aralkyl, carbocycle, heterocycle, and secondary or tertiary alkyl having 3 or more carbons, and where substituents on adjacent chiral carbon atoms may together form a ring.
A catalytic organometallic composition, effective to catalyze the enantioselective alkylation of an allyl group bearing a leaving group at an allylic position, wherein the composition is the product of a process which comprises:
- contacting with a chiral ligand L1, in a suitable solvent, a soluble complex of a metal selected from tungsten (0), chromium (0), and molybdenum(0), having ligands which form a stable complex with the metal and are displaceable by ligand L1 under the conditions of said contacting,
- wherein said ligand L1 comprises:
- a chiral component derived from a chiral diamine, said component comprising first and second carbon atoms, each bearing a binding group —NH—(C═O)—B, wherein
- said carbon atoms are connected by a direct bond or by a chain of one to three atoms comprising linkages selected from alkyl, alkyl ether, alkyl amino, and combinations thereof;
- each group B is selected from alkyl, cycloalkyl, heterocycle, aryl, and aralkyl;
- at least one group B is a N-heterocyclic or N-heteroaryl group CyN having an sp2 hybridized ring nitrogen atom effective to coordinate to said metal atom;
- and
- at least one of said carbon atoms is a chiral carbon atom bearing a further substituent, wherein said substituent or substituents are independently selected from aryl, aralkyl, carbocycle, heterocycle, and secondary or tertiary alkyl having 3 or more carbons, and where substituents on adjacent chiral carbon atoms may together form a ring;
- whereby said complex undergoes a ligand exchange reaction, such that chiral ligand L1 becomes coordinated to said metal atom.
Dependencies are inferred from the claim text.