| abstract |
The present invention provides novel compounds and ligands that are useful in transition metal catalyzed cross-coupling reactions. For example, the compounds and ligands of the present invention are useful in palladium or gold catalyzed cross-coupling reactions. The ligands are of formula (I) wherein each of R1 and R2 is independently selected from tert-butyl, cyclohexyl, 2-tolyl, or 1-adamantyl; each of R3 and R4 is independently selected from a C1-5 alkyl, or R3, R4, and the nitrogen atom to which they are attached form an optionally substituted 4 -10 membered heterocyclic ring; each of X1a and X1b, is independently selected from N or C-R5; each of X2a and X2b, is independently selected from N or C- R6; each R5 is independently selected from -H, -CH3, -OCH3, halogen, or -CF3; each R6 is independently selected from -H, -CH3, -OCH3, -N(CH3)2, halogen, or -CF3; or an R5 and an R6 located on adjacent carbon atoms together with the carbon atoms to which they are attached form an optionally substituted 5-7 membered heterocyclic or carbocyclic ring; or two R6 groups together with the carbon atoms to which they are attached form an optionally substituted 5-7 membered heterocyclic or carbocyclic ring; and wherein no more than one of X1a, X1b, X2a, or X2b is N. |