Stereoselective synthesis of microcarpalide

The first total synthesis of the naturally occurring nonenolide, microcarpalide, is described. The key step in the synthesis was the ring-closing metathesis of a dienic ester prepared in turn by coupling an acid and an alcohol stereoselectively synthesized from (S,S)-tartaric acid and (R)-glycidol, respectively. [structure: see text]     

Stereoselective synthesis of microcarpalide

Microcarpalide is a strong microfilament disrupting agent. The convergent and stereoselective synthesis of microcarpalide was succeeded via Julia olefination and macrolactonization.     

Stereoselective total synthesis of xyolide

A stereoselective total synthesis of xyolide is described employing MacMillan α-hydroxylation, Steglich esterification, and ring closing metathesis as key steps. The use of organocatalytic MacMillan α-hydroxylation to construct two of the chiral centers of the xyolide makes this approach attractive.     

Stereoselective total synthesis of dihydrocorynantheol

[reaction: see text] A stereoselective synthesis of the indole alkaloid dihydrocorynantheol (1) from indole-3-acetic acid has been achieved by a sequence involving 9 as a key intermediate. The synthesis of the unsaturated lactam ring in 9 highlights a series of catalytic organometallic reactions featuring two ring-closing metatheses and a zirconocene-catalyzed carbomagnesation. Since no protecting groups were used, the present synthesis of 1 is exceedingly concise, consisting of only eight distinct operations.     

Total synthesis of microcarpalide

A total synthesis of the natural product microcarpalide is described. Ring-closing metathesis of a dienic ester was used as the key step. Mannose was used as the chiral pool material for the construction of the olefinic-acid and a Sharpless asymmetric dihydroxylation reaction provided the chiral precursor for the synthesis of the olefinic-alcohol.     

Total synthesis of microcarpalide

[reaction: see text] An efficient, convergent approach for the total synthesis of microcarpalide (1) is described. The synthetic strategy features the Sharpless asymmetric dihydroxylation, regioselective epoxide opening with various nucleophiles such as a lithium acetylide and cuprates derived from the vinyl stannane and the vinyl iodide for the construction of a C7-C8 trans-double bond and Yamaguchi macrolactonization as the key steps.     

Stereoselective total synthesis of bazzanene

3azzanene, the stereoisomer of trichodiene, isolated from a liverwort was synthesized with complete stereoselectivity in 8 steps (12% yield) starting from a known bicyclo[2.2.2]octane derivative.     

Stereoselective total synthesis of dodoneine

The stereoselective total synthesis of the naturally occurring bioactive dihydropyranone dodoneine has been achieved involving the Sharpless asymmetric epoxidation, 1,3-syn diastereoselective reduction and Grubb’s ring-closing metathesis as key steps.     

Stereoselective total synthesis of muconin

An antitumor acetogenin, muconin, was synthesized through a coupling reaction of a THF-THP segment and a terminal butenolide. The key reactions include successive ether-ring formation reaction under acidic and basic conditions or one-pot double cyclization promoted by TBAF and stereoselective reduction of acyclic ketones adjacent to the 2,6-cis THP with Zn(BH₄)₂.     

Stereoselective total synthesis of almorexant

A highly stereoselective synthesis of almorexant has been achieved using (R)-tert-butanesulfinamide as a chiral source. The chiral tetrahydroisoquinoline core was constructed through allylation of chiral N-sulfinyl imine followed by ring closure of the secondary amide with a tethered halide. The chiral α-phenyl amide was introduced by means of S_N2 substitution of (S)-methyl 2-phenyl-2-(tosyloxy)acetate with chiral tetrahydroisoquinoline.     

Stereoselective total synthesis of nemorosone

The highly stereoselective total synthesis of nemorosone via a new approach to the bicyclo[3.3.1]nonane-2,4,9-trione core which features intramolecular cyclopropanation of an α-diazo ketone, stereoselective alkylation at the C8 position, and regioselective ring-opening of cyclopropane is described. The total synthesis of nemorosone includes chemo- and stereoselective hydrogenation directed by the internal alkene.     

Stereoselective total synthesis of stagonolide-C

The highly stereoselective synthesis of a biologically active stagonolide-C has been described. The pivotal functionalities are derived from Barbier allylation, an epoxidation by m-CPBA, a chiral-auxiliary mediated acetate aldol addition, a 1,3-anti-reduction, a Sharpless kinetic resolution, a Yamaguchi macrolactonization, and ring-closing metathesis.     

Stereoselective total synthesis of Patulolide C

Abstract

Stereoselective total synthesis of Patulolide C has been accomplished from easily available and inexpensive (S)-chiral epoxide. The key steps involved in the concise synthesis of Patulolide C utilizes ring opening of chiral epoxide, cleavage of 1,2-diol, deprotection of benzyl ether of hydroxyl acid and Yamaguchi macrolactonisation dilution conditions as key steps. The advantage of this method include inexpensive starting material, mild reaction conditions and high purity of products.     

Stereoselective total synthesis of (+)-cardiobutanolide

Stereoselective synthesis of styryllactone (+)-cardiobutanolide was accomplished in good overall yield from d-(-)-tartaric acid. Key features of the synthesis include the elaboration of a gamma-hydroxy butyramide obtained from the dimethylamide of tartaric acid, involving a combination of the addition of 1,3-dithian-2-yllithium and stereoselective reduction.     

Stereoselective total synthesis of (+)-aspicilin

A stereoselective synthesis of (+)-aspicilin is described. Regio- and stereoselective functionalization by intramolecular participation of the sulfinyl group, ene reaction, and macrolactonization by Wadsworth-Emmons reaction employing Masamune-Roush protocol are the key steps of the route.     

Stereoselective total synthesis of (+)-boronolide

A seteroselective total synthesis of (+)-boronolide is described. The key steps are Sharpless asymmetric dihydroxylation, Shibasaki's asymmetric Henry reaction, asymmetric allylation and ring closing metathesis.     

Stereoselective total synthesis of ieodomycin C

A concise stereoselective synthesis of the marine natural product ieodomycin C (3) has been achieved from commercially available pyridinium-1-sulfonate (8) in eight linear steps and 14% overall yield. The key synthetic steps included a B-alkyl Suzuki–Miyaura cross-coupling reaction and an Evans–Nagao acetate aldol reaction. The same synthetic sequence was used for preparing the enantiomer of ieodomycin C (3). Our efforts confirmed the structure of the antibacterial natural product 3.