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.     

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 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.     

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.     

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.     

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.     

The synthesis of (−)-cis- and (−)-trans-crobarbatic acid

The synthesis of both cis- and trans-crobarbatic acid is reported. The five-step sequence proceeds in high yield and with control of both relative and absolute stereochemistry. The key step in the synthesis is the Birch reductive alkylation of a chiral furoic acid which sets the absolute stereochemistry of the products. The stereochemistry of the compounds described was proven unambiguously by X-ray crystallography on one synthetic intermediate and on trans-crobarbatic acid.     

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.     

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.     

Total synthesis of (−)-cleistenolide and formal synthesis of herbarumin I via a diastereoselective modulable allylation

A modulable tin based allylation method for the synthesis of 1,2,3-triols is described. The optimization of the reaction was aided by ¹H and ¹¹⁹Sn low temperature NMR spectroscopic investigations, which support the formation of two cyclic intermediates after transmetallation. Depending on the nature of the Lewis acid, either syn/anti or anti/syn configured triols could be obtained with good stereocontrol. To demonstrate the value of this methodology and the resulting scaffolds, they were used to install the signature triol motifs of (?)-cleistenolide and of herbarumin I.     

Catalytic borylation of o-xylene and heteroarenes via C–H activation

Iridium and rhodium complexes catalyze the borylation of xylene and different heteroarenes using pinacolborane via C–H activation. Various five-membered heterocycles such as thiophene, pyrrole, thionaphthene, and indole derivatives yield the borylated products in moderate to good yields. In general, the reactions proceed with high selectivity to give borylation ortho to the heteroatom.     

Asymmetric synthesis of (S)-(−)-tetrahydropalmatine and (S)-(−)-canadine via a sulfinyl-directed Pictet–Spengler cyclization

(S)-(?)-Tetrahydropalmatine 2 and (S)-(?)-canadine 4 were synthesized in three steps from (S)-6, in 33% and 34% overall yield, respectively. Thus, condensation of the (S)-(E)-sulfinylimines 10 and 11 with the carbanion derived from (S)-6 gave the tetrahydroisoquinolines 12 and 13, respectively, which upon TFA induced N-desulfinylation, and subsequent microwave assisted Pictet–Spengler cyclization effected both cyclization and C-desulfinylation producing (S)-(?)-tetrahydropalmatine 2 and (S)-(?)-canadine 4 in optically pure form.     

The total syntheses of (−)-indicine N-oxide and intermedine N-oxide

The total syntheses of (−)-indicine N-oxide, the enantiomer of natural indicine N-oxide and intermedine N-oxide have been achieved.     

A total synthesis of polyether antibiotic (−)-A23187 (calcimycin)

A total synthesis of (−)-A23187 (calcimycin) was accomplished by a convergent approach. The key step of synthesis was the stereospecific cyclization of the β-hydroxy ketone into the spiroketal under basic conditions.     

A concise synthesis of (−)-lentiginosine via an anti,syn-oxazine

A concise and stereocontrolled total synthesis of (−)-lentiginosine, a potent glycosidase inhibitor, has been achieved. Starting from anti,syn-oxazine as a chiral building block, the key features in these strategies are the Wittig reaction and cyclization.