105708-56-3

A convenient synthesis of the traditional medicine constituents magnolamide, lobechine and funebral is described. Construction of the 2-formylpyrrole core of these natural products was achieved by means of a Maillard reaction, involving condensation of the sugar surrogate, dihydropyranone 9, with the requisite primary amines. This approach offers a very direct and general route to the 2-formylpyrrole ring system. The synthesis of the 2-formylpyrrole core found in the traditional medicine constituents, magnolamide, lobechine and funebral, was constructed by a Maillard reaction, involving condensation of the sugar surrogate, dihydropyranone 9, with the requisite primary amines. This approach offers a very direct and general route to the 2-formylpyrrole ring system. Copyright

A convenient synthesis of the traditional medicine constituents magnolamide, lobechine and funebral is described. Construction of the 2-formylpyrrole core of these natural products was achieved by means of a Maillard reaction, involving condensation of the sugar surrogate, dihydropyranone 9, with the requisite primary amines. This approach offers a very direct and general route to the 2-formylpyrrole ring system. The synthesis of the 2-formylpyrrole core found in the traditional medicine constituents, magnolamide, lobechine and funebral, was constructed by a Maillard reaction, involving condensation of the sugar surrogate, dihydropyranone 9, with the requisite primary amines. This approach offers a very direct and general route to the 2-formylpyrrole ring system.

The stereoselective total synthesis of (-)-funebrine from 2-butyn-1-ol was described. The crucial steps in the synthesis involved the stereoselective enolate Claisen rearrangement of the (S)-α-acyloxy-α-alkynylsilane 8, the Au-catalyzed regio- and stereoselective lactonization of the allenylsilane 7, and the Paal-Knorr pyrrole condensation using an unsymmetrical 1,4-diketone 4b.

The first syntheses of (-)-funebrine [(-)-1] and (-)-funebral [(-)-2] are described. The syntheses feature sequential formation of nitrone VI from methyl glyoxylate (5) with oxime 6, transesterification of nitrone VI with (E)-crotyl alcohol (4), and intramolecular cycloaddition of the resulting nitrone VII bearing crotyl ester to afford cycloadduct 7 as a major product. The adduct 7 was readily elaborated to amino lactone (-)-3, the key synthetic intermediate of (-)-1 and (-)-2.