First total synthesis of (−)-aplyolide A

The first total synthesis of (−)-aplyolide A², (16S)-methyloxacyclohexadeca-(5Z,8Z,11Z,14Z)-tetraen-2-one, 1 is reported. The synthesis is based on three consecutive couplings of terminal alkynes with propargylic halides and proves the absolute configuration of the stereogenic center of the natural product.     

First stereoselective total synthesis of (−)-stagonolide A

The first stereoselective total synthesis of the nonenolide (?)-stagonolide A is described. Olefin metathesis and epoxide opening reaction are the key steps involved.     

First enantioselective total synthesis of (S)-(−)-longianone

An efficient stereoselective synthesis of (S)-(?)-longianone was achieved from sugar derived 1,2-cyclopropanecarboxylate involving bromonium ion mediated solvolytic ring opening and a one-pot dehydrohalogenation, stereoselective intramolecular hetero Michael addition (IHMA) and ester hydrolysis as key steps.     

Enantiospecific total synthesis of (−)-crotanecine

Crotanecine is the necine base component of a number of pyrrolizidine alkaloids. This necine subunit is an amino triol bearing a primary allylic alcohol characterized by an all-cis relationship of its stereocenters. The synthesis of crotanecine has been accomplished using simple yet versatile ring construction approach using ribose as chiral starting point.     

Convergent total synthesis of (−)-dactylolide

A convergent total synthesis of (?)-dactylolide is described. Constructing the 2,6-disubstituted exo-methylene THP moiety was achieved by the intramolecular allylation of α-acetoxy ether. The cyclization precursor was prepared from two segments, an alcohol and carboxylic acid derivatives, by esterification followed by reductive acetylation.     

Asymmetric total synthesis of (−)-rasfonin

An efficient chemoenzymatic asymmetric synthesis of pyranone containing natural product (?)-rasfonin is presented here. Enantioselective enzymatic desymmetrization (EED) and a unique Gluconobacter oxydans mediated oxidative kinetic resolution (OKR) have been successfully employed to install three stereocenters (C_6′, C₇, and C₉) of the target molecule. Stereoselective Achmatowicz reaction of a properly decorated furyl nucleus led to the core pyranone structure of rasfonin. At the late stage of the synthesis Negishi coupling has been used to complete the synthesis.     

The total synthesis of (−)-indolactam I

The first total synthesis of (−)-indolactam I (1) is reported. An efficient synthetic route was established to furnish the natural product in 8 steps. This strategy employed a copper-catalyzed amino acid arylation, peptide coupling, and Lewis acid-mediated macrocyclization to yield 1 from readily available building blocks. In addition, the cell growth inhibition activity of the natural product was examined through assays with the K562 leukemia cell line.     

First stereoselective total synthesis and reconfirmation of absolute structure of nonenolide (−)-stagonolide D

The first stereoselective total synthesis of nonenolide (?)-stagonolide D has been accomplished. Midland Alpine borane reduction to install hydroxyl group at C4, Henbest epoxidation to introduce epoxide stereoselectively between C7 and C8, Yamaguchi esterification and Olefin metathesis reaction are the key steps involved in the total synthesis.     

Protecting-group-free catalytic asymmetric total synthesis of (−)-rosmarinecine

The protecting-group-free asymmetric total synthesis of (?)-rosmarinecine was achieved in only four steps from the commercially available (±)-3-hydroxypyrrolidine hydrochloride (2a). The key steps include the direct oxidation of (±)-2a to (±)-3-hydroxy-1-pyrroline N-oxide (1a) using the Davis reagent and the domino reaction; viz., the lipase-catalyzed dynamic kinetic resolution of (±)-1a with 1-ethoxyvinyl ethyl maleate followed by the intramolecular [3+2] dipolar cycloaddition reaction of the generated optically active ester. Some insights into the mechanism of the racemization of the optically active 1a, observed during the enzymatic process, were also obtained.     

Asymmetric total synthesis of (+)-isocryptotanshinone and formal synthesis of (−)-cryptotanshinone

The first asymmetric total synthesis of (+)-isocryptotanshinone was achieved in 12 linear steps with 12% overall yield from commercially available dihydrobenzopyrone. The key step was a base-mediated cyclization reaction. In addition, the synthetic strategy included the formal synthesis of (−)-cryptotanshinone.     

Efficient enantiodivergent total synthesis of (+) and (−)-bromoxone

The total synthesis of (+)-bromoxone and a formal synthesis of (?)-bromoxone were performed in a simple chemoenzymatic manner, starting from bromobenzene, and using an enantiodivergent strategy. The usefulness of chiral cyclohexadienediols derived from the biotransformations of monosubstituted-aromatic compounds as building blocks for the preparation of natural epoxyenones was confirmed.     

Stereocontrolled total synthesis of the macrocyclic lactone (−)-aspicilin

The essential features of the enantiocontrolled total synthesis of (−)-aspicilin are the strategic use of the photochemical rearrangement of α,β-epoxy diazomethyl ketones to 4-hydroxyalkenoates (Scheme 1) and the stereochemical control of the Sharpless epoxidation, α,ω functionalization of an alkynol using potassium 3-aminopropylamine (KAPA) as acetylene zipper, coupling between C₇ and C₈ by means of a Wittig reaction and lactonization by using 2,6-dichlorobenzoyl chloride.     

First total synthesis of (±)-trolline

Trolline, a new bioactive alkaloid was isolated in 2004. We reported herein the first total synthesis of (±)-trolline, in two steps and 18.0% overall yield.     

First total synthesis of(±)-sepicanin A

<正>A facile approach for the first total synthesis of naturally occurring geranylated flavanoids sepicanin A has been obtained with total yield 16%starting from 2,4,6-trihydroxyacetophenone after four steps.The key step was the protic acids(HCl or p-TsOH)-catalyzed benzopyrone formation in a protic polar solvent by deprotection and cycUzation of chalcone in one step.     

First total synthesis of (±)-abyssinoflavanone V

The total synthesis of (±)-abyssinoflavanone V was first achieved through C-prenylation, selective protection of phenolic hydroxyl group, aldol condensation, cyclization and deprotection starting from cheap 4-hydroxybenzaldehyde and 2,4,6-trihydroxyacetophenone, with total yield 24%. All structures of new compounds were confirmed by IR, 1H NMR and MS.     

First total synthesis of （±）-abyssinoflavanone V

The total synthesis of （±）-abyssinoflavanone V was first achieved through C-prenylation, selective protection of phenolic hydroxyl group, aldol condensation, cyclization and deprotection starting from cheap 4-hydroxybenzaldehyde and 2,4,6- trihydroxyacetophenone, with total yield 24%. All structures of new compounds were confirmed by IR, 1^H NMR and MS.     

The first total synthesis of (−)-sinulariol-B and three other cembranoids

The first total synthesis of (−)-sinulariol-B, a marine cembrandiol, was achieved from geraniol. Three other cembranoids were also synthesized from (−)-sinulariol-B.     

Stereoselective total synthesis of (−)-zeylenol,a key intermediate for the synthesis of (+)-pipoxide, (−)-uvarigranol G and (−)-tonkinenin A

Total synthesis of (?)-zeylenol, a key intermediate for the synthesis of (+)-pipoxide, (?)-uvarigranol G and (?)-tonkinenin A was achieved from commercially available starting material d-mannose. The key steps are mixed aldol condensation, Grignard reaction, ring closing metathesis and regioselective benzoylation.