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.     

Convenient synthesis of highly optically active 2,3,4,6-tetrasubstituted tetrahydropyrans via Prins cyclization reaction (PCR) of optically active homoallylic alcohols with aldehydes

Prins cyclization reaction (PCR) of optically active homoallylic alcohols, R^aC^*H(OH)CH₂CHCHCH₃ (1-substituted but-2-en-1-ol), with aldehydes (R^bCHO) in the presence of an acid-catalyst (HX) affords (2-R^b,3-CH₃,4-X,6-R^a)-tetrasubstituted tetrahydropyrans highly stereoselectively in good yields.     

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.     

Synthesis of an austrodorane sesquiterpenoid core via a transannular Prins cyclization

The bicyclo[4.3.0]nonane core of the austrodorane family of sesquiterpenoids has been synthesized via a novel transannular Prins cyclization. This strategy formed the fused 5,6-ring system and installed the required quaternary stereocentre at the ring fusion in a single step.     

RCM approach for the total synthesis of cryptophycin-24 (Arenastatin A)

An efficient total synthesis of cryptophycin-24 (arenastatin A) is reported, which features two novel synthetic strategies, the use of a RCM reaction to form the macrocycle, and the introduction of the styrene epoxide moiety prior to the macrocyclization reaction.     

Unexpected Prins cyclization: iron-promoted cyclization/hydration of alkynyl-dimethyl acetals

Unexpected products containing acyl-substituted unsaturated seven-membered carbocycle were synthesized by FeCl₃-promoted intramolecular Prins cyclization of alkynyl-dimethylacetals in good yields. It is remarkable that the synthesized 7-exocyclic vinyl cations generated as a result of Prins-type cyclization were trapped by H₂O (no halogen ion) in CH₂Cl₂ to give the corresponding enol derivatives. Those enol derivatives underwent enol-keto tautomerism and then eliminated one molecule of MeOH to give the corresponding acyl-substituted unsaturated seven-membered carbocycle.     

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.     

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.     

Application of Prins cyclization to the total synthesis of (+)-decytospolides A and B

(+)-Decytospolides A and B, natural products containing the tetrahydropyran skeleton, were synthesized via Prins cyclization as the key step.     

Stereochemical Prins cyclization: electronic versus steric effects on the synthesis of 2,4,6-trisubstituted tetrahydropyran rings

A convenient approach towards the synthesis of both syn- and anti-2,4,6-chlorotetrahydropyrans has been developed. The electronic and steric influences on the stereochemistry of the Prins cyclized products were investigated based on the substituents of the homoallylic alcohol.     

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.     

The stereoselective total synthesis of xestodecalactone C and epi-sporostatin via the Prins cyclisation

Syntheses of xestodecalactone C and epi-sporostatin are described utilising Prins cyclisations, Mitsunobu reaction and intramolecular Friedel-Crafts acylation. The approach is convergent and highly stereoselective.     

Stereoselective synthesis of tarchonanthuslactone via the Prins cyclisation

The stereoselective total synthesis of tarchonanthuslactone, a polyketide natural product, has been achieved. The synthesis exploits the high stereochemical control in the Prins cyclisation along with ring closing metathesis (RCM) as a key step.     

Stereoselective synthesis of simplactone B via Prins cyclisation

The synthesis of simplactone B has been achieved through a series of nine steps in 85% overall yield using Prins cyclisation as the key step with high stereochemical control.     

A Tandem Olefin Migration and Prins Cyclization Using Cu(OTf)(2)-Bisphosphine Complexes: An Improved Synthesis of Functionalized Tetrahydropyrans

In situ-generated (bis-DPPMB)-Cu(OTf)₂ complex has been examined to catalyze a tandem olefin migration and Prins cyclization of an alkenol with various aldehydes. The reaction proceeded with electron-rich aromatic aldehydes at room temperature and provided functionalized tetrahydropyrans in good yields. An efficient synthesis of the bis-DPPMB ligand has also been described.     

Stereoselective synthesis of basiliskamides A and B via Prins cyclisation

A stereoselective and convergent approach to basiliskamides A and B is achieved through our recently developed strategy for the construction of polyketide precursors via Prins cyclisation. The approach mainly relies upon reductive opening of 1-iodomethyl cyclic ethers, Mitsunobu inversion, Takai olefination and Stille coupling along with Prins cyclisation.     

A short and efficient synthesis of honokiol via Claisen rearrangement

A concise and efficient total synthesis of honokiol, a biphenyl-type neolignan is accomplished in six steps using readily available and cost-effective reagents. The synthetic route involves mainly the Grignard reaction, iodine mediated aromatization, and Claisen rearrangement as key steps. A predominant formation of honokiol (1a) was observed in the Claisen rearrangement under microwave irradiation whereas the isohonokiol (1b) was formed as a major product under conventional conditions.