Synthesis of 4-diphenylphosphanylmethyl- and 4-phenylthiomethyl-1,4-methano-11,11-dimethyl-1,2,3,4-tetrahydroacridine: new N–P and N–S camphor-derived chiral ligands for asymmetric catalysis

A new procedure has been developed for the preparation of camphor-annulated quinoline with different substituents on the 1-methyl group of the (+)-camphor backbone. Amongst them, two new N–P and N–S ligands, namely the 4-(diphenylphosphanylmethyl)- and 4-(phenylthiomethyl)-1,4-methano-11,11-dimethyl-1,2,3,4-tetrahydroacridine, have been employed in asymmetric palladium-catalyzed allylic substitution.

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4-Diphenylphosphanylmethyl-1,4-methano-11,11-dimethyl-1,2,3,4-tetrahydroacridineC29H28NP[α]D25=+29.4 (c 0.48, CHCl3)Absolute configuration: 1S,4SPrepared from (+)-camphor

4-Diphenylphosphanylmethyl-1,4-methano-11,11-dimethyl-1,2,3,4-tetrahydroacridine P-boraneC29H31BNP[α]D25=-146.3 (c 2.0, CHCl3)Absolute configuration: 1S,4SPrepared from (+)-camphor

4-Phenylthiomethyl-1,4-methano-11,11-dimethyl-1,2,3,4-tetrahydroacridineC23H23NS[α]D25=-7.2 (c 0.67, CHCl3)Absolute configuration: 1S,4SPrepared from (+)-camphor

4-Iodomethyl-1,4-methano-11,11-dimethyl-1,2,3,4-tetrahydroacridineC17H18IN[α]D25=-49.3 (c 0.13, CHCl3)Absolute configuration: 1S,4SPrepared from (+)-camphor

4-Hydroxymethyl-1,4-methano-11,11-dimethyl-1,2,3,4-tetrahydroacridineC17H19BNO[α]D25=+21.3 (c 0.72, CHCl3)Absolute configuration: 1S,4SPrepared from (+)-camphor

4-Benzyloxymethyl-1,4-methano-11,11-dimethyl-1,2,3,4-tetrahydroacridineC24H25NO[α]D25=+50.7 (c 3.22, CHCl3)Absolute configuration: 1S,4SPrepared from (+)-camphor

1-Benzyloxymethyl-7,7-dimethylbicyclo[2.2.1]heptan-2-oneC17H22O2[α]D25=+38.0 (c 1.77, CHCl3)Absolute configuration: 1R,4RPrepared from (+)-camphor