ABSTRACT
The total synthesis of protoporphyrin IX and its disodium salt using a new alternative method to the classical MacDonald condensation is reported. The key step is the reaction of the new unsymmetrical diiodo dipyrrylmethane 1 with the known dipyrrylmethane 2. Coupling of the two fragments leads directly to porphyrin 3 without the need of an oxidizing agent. The new methodology is well suited for the synthesis of protoporphyrin IX derivatives on a multi-100 g scale in good quality without the need for chromatography. Furthermore, these preparations are completely free of any contaminant of animal origin, which represents a real improvement in the manufacturing of protoporphyrin IX derivatives.
Subject(s)
Hematoporphyrins/chemical synthesis , Protoporphyrins/chemical synthesis , Sodium/chemistry , Molecular StructureABSTRACT
An operationally simple and scalable synthesis of enantiomerically pure bicyclo[2.2.2]octadiene (bod*) ligands relying on an organocatalytic one-pot Michael addition-aldol reaction with cheap 2-cyclohexenone and phenylacetaldehyde is presented. The crystalline bicyclic product 4a (6-hydroxy-5-phenylbicyclo[2.2.2]octan-2-one) is transformed into phenylbicyclo[2.2.2]oct-5-en-2-one 2, a versatile starting material for the 2-step synthesis of both symmetrical, such as Hayashi's Ph-bod* ligand, as well as novel unsymmetrical chiral dienes.
Subject(s)
Acetaldehyde/analogs & derivatives , Bridged Bicyclo Compounds/chemistry , Bridged Bicyclo Compounds/chemical synthesis , Cyclohexanones/chemistry , Acetaldehyde/chemistry , Catalysis , Ligands , Molecular Structure , StereoisomerismABSTRACT
A Ni(0)-BINAP system is utilized for the highly enantioselective alpha-arylation of alpha-substituted gamma-butyrolactones with aryl chlorides and bromides. alpha-Quaternization is achieved in moderate to excellent yields. Furthermore, the rate accelerating effect caused by the addition of Zn(II) salts is investigated.
