Complexity generation by chemical synthesis: a five-step synthesis of (-)-chaetominine from L-tryptophan and its biosynthetic implications.

We demonstrated, for the first time, that on the basis of chemistry principles, the hexacyclic peptidyl alkaloid (−)-chaetominine (1) can be synthesized in a straightforward manner from L-Trp. The approach features the efficient generation of molecular complexity via a tandem C3/C14 syn-selective epoxidation (dr = 3:2)­annulative ring-opening reaction and a regioselective epimerization at C14. The successful production of (−)-chaetominine (1) from L-Trp could be helpful for revealing how the configuration of L-tryptophan becomes inverted in the biosynthetic pathway of (−)-chaetominine (1).

SmI2-mediated coupling of nitrones and tert-butanesulfinyl imines with allenoates: synthesis of ß-methylenyl-γ-lactams and tetramic acids.

Nitrones and tert-butanesulfinyl imines undergo conjugate addition to alkyl allenoates under SmI(2)-mediated reductive coupling conditions to produce novel ß-methylenyl-substituted γ-amino esters. The latter were readily transformed into the corresponding ß-methylenyl-γ-lactams by simple zinc reduction (N-hydroxy amines) or by acid hydrolysis (sulfinamides). The diastereoselective preparation of various ß-methylenyl-γ-lactams offers a route to tetramic acids, the key structural features of an important class of bioactive natural products.

Efficient and chemoselective alkylation of amines/amino acids using alcohols as alkylating reagents under mild conditions.

We report a mild and environmentally benign method for the synthesis of tertiary amines using alcohols as the alkylating reagents. Not only secondary amines such as piperazines but also amino acids and amino alcohols can be N-alkylated selectively. For N,O-benzyl protected amino alcohols, both N,O-de-benzylation and N-methylation were achieved in one-pot.