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.     

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.     

First total synthesis of (−)-salprzelactone

The first enantioselective total synthesis of (?)-salprzelactone, a seco-norabietane diterpenoid has been accomplished in only three steps. Key transformations of the synthesis include an intermolecular aldol reaction and lactonization.     

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.     

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.     

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.     

A stereocontrolled total synthesis of (±)-saframycin A

A thirteen-step total synthesis of (±)-saframycin A from a tricyclic lactam intermediate is described. The key step of this total synthesis is the stereocontrolled construction of a pentacyclic saframycin framework via a modified Pictet-Spengler type cyclization generating a bis-carboxylic acid ester derivative, followed by decarboxylation. The cytotoxicity profiles are also presented.     

A rapid formal synthesis of the macrolide (−)-A26771B

(−)-A26771B, a novel 16-membered macrolide with antibiotic activity, has been formally synthesized. In the synthesis ruthenium catalyzed ring-closing olefin metathesis (RCM) was used as a key reaction to construct the lactone ring.     

Concise total synthesis of (-)-myxalamide A

The MIDA touch: A concise and highly convergent protecting-group-free total synthesis of (-)-myxalamide?A involves a stereoselective vinylogous Mukaiyama aldol reaction of a vinylketene silyl N,O-acetal, together with a one-pot Stille/Suzuki-Miyaura cross-coupling reaction using Burke's N-methyliminodiacetic acid (MIDA) boronate to connect left- and right-hand fragments of the molecule (see scheme).     

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.     

Improved total synthesis of (±)-Tetragocarbone A

Stereoselective total synthesis of (±)-tetragocarbone A isolated from the propolis of an Australian stingless bee, Tetragonula carbonaria, has been developed by focusing on the latent symmetry of 1. The requisite 1R*, 3R*, 6S* stereogenic centers were selectively installed by hydroxy group directing reactions including the late stage desymmetrization of the 1,3-diketone. The target natural product was successfully prepared in 12 steps from phloroglucinol on 300 mg.     

A formal total synthesis of (±)-strigol

A novel route to the tricyclic compound (±)-6, a known precursor to (±)-strigol is disclosed.     

A concise total synthesis of (±)-minfiensine

A concise total synthesis of (±)-minfiensine using all conventional methods and starting from commercial materials has been completed. The synthesis features a Fischer indole synthesis, a Heck alkylation of an intermediate ketone enolate, conversion of a ketone carbonyl into an epoxide, and transformation of the latter into an allylic alcohol.     

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.