Total synthesis of cryptophycin-24 (arenastatin A) via Prins cyclization

A stereoselective synthesis of fragment A of cryptophycin is achieved utilizing the versatile Prins cyclization. Subsequently, the total synthesis of cryptophycin-24 (arenastatin A) has been accomplished by coupling it with the depsipeptide subunit.     

An efficient approach to the synthesis of 3-vinylidene tetrahydropyrans via Prins-type cyclization

Lewis acid-catalyzed intramolecular reactions of oxocarbenium ions with propargylsilanes are described. The results obtained indicate that trimethylsilyl trifluoromethanesulfonate (TMSOTf) efficiently catalyses cyclization leading to the corresponding 3-vinylidene tetrahydropyrans in high yield as single isomers.     

Total synthesis of (+/−)-diospongin A via Prins reaction

A straightforward synthesis of (+/−)-diospongin A starting from benzaldehyde is described. A Prins cyclization reaction to control the relative configuration of the three stereogenic centers and a Mitsunobu inversion represent the key steps of the approach.     

A concise stereoselective formal total synthesis of the cytotoxic macrolide (+)-Neopeltolide via Prins cyclization

A convergent and highly stereoselective formal total synthesis of the naturally occurring, cytotoxic 14-membered macrolide neopeltolide has been achieved via two Prins cyclizations.     

Highly stereoselective prins cyclization of (Z)- and (E)-gamma-brominated homoallylic alcohols to 2,4,5,6-tetrasubstituted tetrahydropyrans

An efficient method has been developed to construct 2,6-cis-4,5-dibromo-tetrasubstituted tetrahydropyran (THP) rings with well-controlled stereochemistry in moderate to high yields.     

Organic-base-catalyzed synthesis of phthalides via highly regioselective intramolecular cyclization reaction

The organic-base-catalyzed 5-exo intramolecular cyclization reaction of o-alkynylbenzoic acid produces the corresponding phthalide regioselectively in good to excellent yields. The method provides a practical access to the phthalides, an important class of biologically active molecules.     

Cu(II)-catalyzed olefin migration and Prins cyclization: highly diastereoselective synthesis of substituted tetrahydropyrans

Metal-ligand complexes of Cu(OTf)(2) with an appropriate bisphosphine ligand have been shown to effectively catalyze the formation of substituted tetrahydropyrans via a sequential olefin migration and Prins-type cyclization. This methodology provides convenient access to a variety of functionalized tetrahydropyrans in excellent diastereoselectivities and good to excellent yields.     

Cellulose-SO3H as a recyclable catalyst for the synthesis of tetrahydropyranols via Prins cyclization

Tetrahydropyranols are prepared in good yields and with high cis-selectivity by means of the Prins cyclization using cellulose-sulfonic acid under mild reaction conditions. This is the first report on the preparation of tetrahydropyranols using epoxides and homoallylic alcohols via Prins cyclization.     

Iodine as a mild and versatile reagent for the synthesis of 1,3-dioxane derivatives via the Prins reaction

Iodine is found to be an effective reagent for the cross-coupling of olefins with aldehydes under mild conditions to produce 4-substituted 1,3-dioxane derivatives in excellent yields and in short reaction times with high selectivity. The use of iodine makes this procedure simple, convenient, cost-effective and practical. This method works not only with formaldehyde but also with acetaldehyde, propionaldehyde and cyclohexanecarboxaldehyde.     

Highly stereocontrolled synthesis of fluorinated 2,6-trans dihydropyrans via Prins cyclization

A highly efficient method for the synthesis of fluorinated 2,6-trans dihydropyrans via BF₃·Et₂O-promoted Prins cyclization of allenic alcohols and aldehydes is developed. Various 2,6-trans fluorodihydropyrans are obtained in moderate to good yields with excellent diastereoselectivities.     

A modified Prins reaction for the facile synthesis of structurally diverse substituted 5-(2-hydroxyethyl)-3,3-dihydrofurane-2(3H)-ones

Furanones are important synthetic intermediates commonly found in natural products, receptor ligands, and drug molecules. Unacceptable yields of substituted furanones obtained using a previously reported Prins reaction led to the development of a modified approach. Readily prepared substituted allylic esters were reacted under Prins reaction conditions catalyzed by a protic acid to provide structurally diverse substituted furanones in modest to good yields. The reaction goes through a protected caprolactone intermediate that was isolated and characterized for selected compounds. The approach supplies an efficient, versatile, and higher yield method for the synthesis of these important heterocyclic intermediates.     

Asymmetric total synthesis of (-)-scabronine G via intramolecular double Michael reaction and Prins cyclization

The enantioselective total synthesis of (-)-scabronine G is described. The key features of the present synthesis include the construction of a 5-6 ring system containing two quaternary carbon centers via a diastereoselective intramolecular double Michael reaction and the formation of a seven-membered ring using a Prins cyclization.     

Stereoselective synthesis of anti-1,3-diol units via Prins cyclisation: application to the synthesis of (−)-sedamine

The scope of the Prins cyclisation, the higher stereoselective synthesis of multisubstituted tetrahydropyrans from aldehydes and homoallylic alcohols, is expanded. A new approach for the stereoselective synthesis of polyketide precursors containing anti-1,3-diols, flanked by a variety of alkyl branches and functional groups is described. The approach is successfully exploited for the synthesis of (−)-sedamine.     

Total synthesis of (−)-ephedradine A: an efficient construction of optically active dihydrobenzofuran-ring via C-H insertion reaction

The stereocontrolled total synthesis of (−)-ephedradine A (1) has been accomplished. Construction of optically active dihydrobenzofuran-ring was performed by a novel asymmetric C-H insertion reaction. After an intramolecular ester-amide exchange reaction and a Sharpless asymmetric aminohydroxylation reaction, construction of the complex macrocyclic ring was performed by Ns-strategy and an intramolecular aza-Wittig reaction.     

An efficient synthesis of highly substituted furans via the electrophilic cyclization of 1-(1-alkynyl)-cyclopropyl ketones

The electrophilic cyclization of 1-(1-alkynyl)-cyclopropyl ketones offers an efficient and straightforward route to highly substituted furans under extremely mild reaction conditions. Iodine, NIS, and PhSeBr have proven successful as electrophiles in this process.     

Chemoselective allylation of aldehydes using cerium(III) chloride: simple synthesis of homoallylic alcohols

Aldehydes undergo smooth nucleophilic addition with allyltributylstannane in the presence of CeCl₃·7H₂O in acetonitrile under extremely mild reaction conditions to afford the corresponding homoallylic alcohols in excellent yields with high chemoselectivity. This method is very useful especially for the allylation of aldehydes bearing acid sensitive functionalities such as TBDMS, THP ethers, acetonides, aryl alkyl ethers and carbamates.     

Novel synthesis and functionalization of ortho-ortho disubstituted biphenyls and a highly condensed novel heterocycle using radical cyclization reaction

This paper describes a novel synthetic route for the preparation of ortho-ortho disubstituted biphenyls and compounds possessing highly condensed ring system represented by structures X and Y, respectively. Several approaches, such as intermolecular Grubb's olefin metathesis, Heck and, Suzuki reactions were incorporated to functionalize the core structures of X and Y making it suitable for the preparation of a library of compounds.     

A diastereoselective construction of pyrazinoisoquinoline skeletons via tandem cyclization of phenylalanine derivatives: a facile synthesis of optically active pyrazinoisoquinolines

A facile and stereocontrolled construction of optically active pyrazinoisoquinoline skeletons based on tandem cyclization of enantiopure phenylalanine derivatives was examined. The reaction provided optically active 6,11b-trans pyrazinoisoquinoline ring systems in excellent diastereoselectivity, and this method was applicable to the cyclization of phenylalanine derivatives with diverse substituents.