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The convergent synthesis of thiophene-3-carboxamide analogues of annonaceous acetogenins was accomplished through the asymmetric alkynylation of a 2-formyl THF ring fragment with an alkyne having a thiophene ring as the key step. Eight stereoisomers of the THF ring moiety were synthesized by this convergent route and their antiproliferative activities against 39 human cancer cell lines were evaluated. It was revealed that derivatives having the threo configuration between C17–C18 positions showed more potent activities than the corresponding erythro ones.

A practical method for the synthesis of chiral β2,3-amino esters having various substituents was developed, which is characterized by an asymmetric Michael addition reaction of a chiral lithium amide with trisubstituted (E)-α,β-unsaturated esters. We found that a highly face-selective protonation occurred by the quick addition of water to the enolate intermediate derived from the Michael addition reaction to afford N-protected β2,3-amino esters in moderate to excellent yields. This finding was made possible by the facile preparation of geometrically pure trisubstituted (E)-α,β-unsaturated esters, which was established recently by our group. The subsequent deprotection of the amino group in the Michael adduct by using N-iodosuccinimide (NIS) efficiently provided β2,3-amino esters having various substituents.

The syntheses of three thiophene-3-carboxamide analogs of annonaceous acetogenins were accomplished, where the obtained analogs bear ethylene glycol units that enhance their water solubilities. Evaluation of their growth inhibitory activities across 39 human cancer cell lines revealed that the analog bearing one ethylene glycol unit in the vicinity of its tetrahydrofuran ring moiety exhibited a comparable potent growth inhibitory activity to the lead compound, and the growth inhibitory patterns of these analogs are similar to those of mitochondrial complex I inhibitors. This result indicates the possibility of discovering new water-soluble antitumor agents derived from acetogenins through the introduction of ethylene glycol units.

Pyrrolophenanthridinone derivatives including the natural products were readily synthesized by samarium(II)-mediated reductive cyclization of aryl radical onto a benzene ring under mild reaction conditions. This methodology was applied to the concise synthesis of anhydrolycorinone, a natural pyrrolophenanthridinone and a precursor of hippadine and anhydrolycorine.

An asymmetric intramolecular Heck reaction that involves the dynamic kinetic resolution of an atropisomer as the substrate furnished a product in high yield with high enantioselectivity. DFT calculations (Spartan'10, B3LYP/6-31G*) confirmed that the reaction proceeded via atropisomerization involving a conformational transformation (half-chair form/distorted-boat form) of the substrate.

The first asymmetric total synthesis of (+)-taiwaniaquinol D and (−)-taiwaniaquinone D isolated from Taiwania cryptomerioides was attained by using the intramolecular asymmetric Heck reaction. The reaction provided a tricyclic intermediate that would be available for the asymmetric total synthesis of various abeo-abietane-type diterpenoids.