Hydroxyquinone annelation

Tius, Marcus A.; Cullingham, Jean M.; ALI, S.

doi:10.1039/c39890000867

Cited by 11 publications

(4 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The presence of the allene function in the products of nucleophilic addition of carbanions such as 1 and 2 confers reactivity due to the strain inherent in the allene, which is often advantageous for synthetic applications . Our interest in 1 was initially as a reagent for the annulation of ketones to hydroxy 1,4‐benzoquinones . Subsequently, we discovered that 1 and 2 were exceptionally useful reagents for the allene ether version of the Nazarov cyclization.…”

Section: Introductionmentioning

confidence: 99%

“…[2] Our interest in 1 was initially as a reagent for the annulation of ketones to hydroxy 1,4-benzoquinones. [3] Subsequently, we discovered that 1 and 2 were exceptionally useful reagents for the allene ether version of the Nazarov cyclization. [ 2f, 4] Lithioallene 2 was the first reagent we developed for the chiral auxiliary controlled asymmetric Nazarov cyclization.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Mixed Aggregates of 1‐Methoxyallenyllithium with Lithium Chloride

2014

Self Cite

View full text Add to dashboard Cite

A combined computational and 13C NMR study was used to investigate the formation of mixed aggregates of 1-methoxyallenyllithium and lithium chloride in tetrahydrofuran (THF) solution. The observed and calculated chemical shifts, as well as the calculated free energies of mixed aggregate formation (MP2/6-31+G(d)), are consistent with the formation of a mixed dimer as the major species in solution. Free energies of mixed dimer, trimer, and tetramer formation were calculated by using the B3LYP and MP2 methods and the 6-31+G(d) basis set. The two methods generated different predictions of which mixed aggregates will be formed, with B3LYP/6-31+G(d) favoring mixed trimers and tetramers in THF solution, and MP2/6-31+G(d) favoring mixed dimers. Formation of the sterically unhindered mixed dimers is also consistent with the enhanced reactivity of these compounds in the presence of lithium chloride. The spectra are also consistent with some residual 1-methoxyallenyllithium tetramer, as well as small amounts of higher mixed aggregates. Although neither computational method is perfect, for this particular system, the calculated free energies derived using the MP2 method are in better agreement with experimental data than those derived using the B3LYP method.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Mixed Aggregates of 1‐Methoxyallenyllithium with Lithium Chloride

2014

Self Cite

View full text Add to dashboard Cite

show abstract

“…The same product was formed when aldehyde 1 or silyl enol ether 3 was treated with BF 3 ·Et 2 O in dichloromethane. The conversion of 1 to 2 is not an oxidation and is catalyzed by the m -chlorobenzoic acid that is present in untreated commercial samples of m -CPBA . Since I thought that the reaction leading to 2 was more interesting than the ortho -quinone synthesis and I recognized the close structural homology between 2 and the methylenomycins, I decided to examine this cyclopentannelation more closely …”

Section: Introductionmentioning

confidence: 99%

Cationic Cyclopentannelation of Allene Ethers

2003

Self Cite

View full text Add to dashboard Cite

The variant of the Nazarov cyclization that makes use of allenyl ethers is suitable for the preparation of diverse, highly functionalized cyclopentenones. Three variants of the basic reaction, differing in the nature of the electrophile that is combined with the allene to prepare the precursor for the pentadienyl cation, are described. One variant, which utilizes an alpha,beta-unsaturated morpholino amide, has been successfully employed in an enantioselective version of the cyclopentannelation.

show abstract

“…Another rather unusual annelation gives rise to various ring fused hydroxybenzoquinones [43]. The method for the preparation of the cyclohexane-fused derivative, 69, is outlined in Scheme 30.…”

Section: Scheme 28mentioning

confidence: 99%