Donghui Ma

Total syntheses of Tardioxopiperazine A, Isoechinulin A, and Variecolorin C.

First total syntheses of the isoechinulin-type alkaloids: Tardioxopiperazine A, Isoechinulin A, and Variecolorin C have been achieved from a common key intermediate 5, which was derived from a regiocontrolled Stille cross-coupling reaction of an allylindium reagent.

Enantioselective total synthesis of (-)-walsucochin B.

The first enantioselective total synthesis of the structurally unique nortriterpenoid (-)-walsucochin B has been accomplished through the cationic polyolefin cyclization initiated by chiral epoxide. The core framework and the stereocenters in the natural product were all constructed in this step. A site-selective, late-stage free-radical halogenation and Seyferth-Gilbert homologation was adopted to install the acetylene moiety to synthesize the phenylacetylene. The absolute configuration of walsucochin B was confirmed through enantioselective total synthesis.

Rapid Construction of the [6-6-6-5] Tetracyclic Skeleton of the Daphniphyllum Alkaloid Daphenylline

You can call me Al: A concise route for construction of the [6-6-6-5] tetracyclic skeleton of daphenylline, a structurally novel Daphniphyllum alkaloid, has been developed with full stereocontrol in only 8 steps from two known fragments. This approach features an intramolecular [3+2] cycloaddition of a 2-azaallyl anion with an alkene to form the cis-fused AC rings.

Concise Total Synthesis of (±)-Dasyscyphin D

The first and efficient total synthesis of (±)-dasyscyphin D was achieved in 9 steps with 22.6% overall yield. The key steps involved a PtCl(2)-catalyzed pentannulation reaction and acid-catalyzed double Robinson annulations.

Protecting-Group-Free Total Synthesis of (−)-Lycopodine via Phosphoric Acid Promoted Alkyne Aza-Prins Cyclization

A protecting-group-free route for the total synthesis of (-)-lycopodine was demonstrated in only 8 steps from Wades fawcettimine enone (12 steps from commercial availiable (R)-(+)-pulegone). The key core of this alkaloid was constructed through a phosphoric acid promoted and highly stereocontrolled alkyne aza-Prins cyclization reaction, synchronously establishing the bridged B-ring and the C13 quaternary stereocenter. Importantly, the synthesis further features a new efficient approach for the preparation of other lycopodine-type alkaloids.

Concise formal syntheses of the Amaryllidaceae alkaloids (±)-tazettine and (±)-6a-epipretazettine: construction of the core skeleton via tandem intramolecular oxidative Friedel-Crafts/aza-Michael reaction.

the MOST (2010CB833200);the NSFC (21125207;21072086;21102062);program 111;the Fundamental Research Funds for the Central Universities (lzujbky-2011-76)

Asymmetric Total Synthesis of (−)-Lycospidine A

The first asymmetric total synthesis of the structurally unique Lycopodium alkaloid (-)-lycospidine A, containing an unprecedented five-membered ring, has been accomplished in only 10 steps with 21.6% overall yield from the known conveniently available sulfoxide. This protecting-group-free short synthesis relied on the use of a key amidation/aza-Prins domino cyclization reaction to rapidly construct the tricyclic skeleton and two continuous stereocenters (one of which is a bridged quaternary stereocenter). An intramolecular aldol condensation was successfully utilized to establish the unique five-membered ring, and a late-stage oxidation inspired by biosynthesis pathway was adopted to synthesize the diosphenol ring of (-)-lycospidine A.

Short and Scalable Total Synthesis of Myrioneuron Alkaloids (±)-α,β-Myrifabral A and B

The first total synthesis of the Myrioneuron alkaloids (±)-α,β-myrifabral A and B has been accomplished in only four steps from conveniently available starting materials. This short synthesis relied on the use of a key tandem Mannich/amidation reaction to rapidly construct the core framework and two carbon stereocenters. The synthetic route allows for large scale preparation of these promising natural products against the hepatitis C virus (HCV).

Biomimetic Total Syntheses of (+)-Dihydrolyfoline and (−)-5-epi-Dihydrolyfoline

The first asymmetric total syntheses of (+)-dihydrolyfoline and (-)-5-epi-dihydrolyfoline have been achieved in five and six steps with 4.6% and 14% overall yields, respectively, in which the chiral biaryl axes were constructed in a highly regioselective and stereoselective manner via a biogenetic enzymatic oxidative couplings of phenols, and the requisite quinolizidinone cores were prepared by an enzymatic Mannich reaction.

Asymmetric Total Synthesis of (-)-Kravanhin B.

The first asymmetric total synthesis of kravanhin B has been accomplished with a linear reaction sequence of 13 steps starting from (R)-(-)-carvone. The synthesis features an intramolecular aldol cyclization to construct the desired cis-fused decalin skeleton and an acid-catalyzed dehydration and olefin isomerization to install the γ-butenolide ring.