Abstract
Dibenzazepinyl dichlorophosphine 2 reacts with (R,R)-2,3-O-isopropylidene-threitol (3) in $Et2_O$ solution to afford gram-quantities of the enantiopure macrocylic phosphoramidite (all-R)-6, which may be seen as a formal dimer of classic phosphoramidite P-alkene hybrid ligands. Complexation experiments with $PdCl_2$ reveal highly selective formation of the trans-dinuclear complex (all-R)-11. The corresponding bulkier and rigidly trans-eclipsed 1,4-diol (S,S)-bis-hydroximethyl-9,10- dihydro-9,10-ethaneanthracene (4), does not favor macrocycle formation and exclusively leads to the new dibenzazepinyl phsophormaidite P-alkene ligand 7, which in Pd-catalyzed asymmetric allylic amination comes the well-known ‘privileged’ binol-derived P-alkene analogue 1 close in terms of enantioselection.
Frieß, Sibylle