Monophosphite ligands having a tert-butyloxycarbonyl group

A ligand having structure I or II:

• wherein
• R1, R2, R3, R4, R5, R6, R7, R8 are each independently selected from the group consisting of:
• —H, —(C1-C12)-alkyl, —O—(C1-C12)-alkyl, —O—(C6-C20)-aryl, —(C6-C20)-aryl, halogen, COO—(C1-C12)-alkyl, CONH—(C1-C12)-alkyl, —(C6-C20)-aryl-CON[(C1-C12)-alkyl]2, —CO—(C1-C12)-alkyl, —CO—(C6-C20)-aryl, —COOH, —OH, —SO3H, —SO3Na, —NO2, —CN, —NH2, and —N[(C1-C12)-alkyl]2;
• X and Y are each independently selected from the group consisting of
• —(C1-C12)-alkyl, —(C6-C20)-aryl, —(C6-C20)-aryl-(C1-C12)-alkyl, —(C6-C20)-aryl-O—(C1-C12)-alkyl, —(C1-C12)-alkyl-(C6-C20)-aryl, —(C6-C20)-aryl-COO—(C1-C12)-alkyl, —(C6-C20)-aryl-CONH—(C1-C12)-alkyl, —(C6-C20)-aryl-CON[(C1-C12)-alkyl]2, —(C4-C20)-heteroaryl, —(C4-C20)-heteroaryl-(C1-C12)-alkyl, and —(C5-C8)-cycloalkyl-(C4-C20)-aryl-CO—(C6-C20)-aryl,
• Z is selected from the group consisting of
• —(C1-C12)-alkyl-, —(C6-C20)-aryl-, —(C6-C20)-aryl-(C1-C12)-alkyl-, —(C1-C12)-alkyl-(C6-C20)-aryl-, —(C4-C20)-heteroaryl-, —(C6-C20)-aryl-CO—(C6-C20)-aryl-, and —(C6-C20)-aryl-(C6-C20)-aryl-;
• wherein the alkyl, heteroalkyl, cycloalkyl, heterocycloalkyl, aryl and heteroaryl groups mentioned are optionally substituted.