The Efficient and Enantiospecific Total Synthesis of Cyclopenta[<i>b</i>]phenanthrenes Structurally‐Related to Neurosteroids

Mei, Qian; Covey, Douglas F.

doi:10.1002/adsc.201000370

Cited by 6 publications

(14 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…20 The adamantyl groups were then added to CP[ b ]Ps 9 and 10 to obtain compounds 11 and 12 , respectively.…”

Section: Resultsmentioning

confidence: 99%

“…Compounds 9 and 10 in the CP[b]P ring system (Scheme 5) were prepared as described previously. 20 The adamantyl groups were then added to CP[b]Ps 9 and 10 to obtain compounds 11 and 12, respectively.…”

Section: Resultsmentioning

confidence: 99%

“…[α] 20 D +110.0 (c = 0.32, CHCl 3 ); 1 H NMR (300 MHz, DMSO-d 6 ) δ 8.74 (s, 1H), 6.58 (s, 1H), 6.32 (s, 1H), 2.50-0.86 (m, 30H), 0.73 (s, 3H); 13 20 D +78.5 (c = 0.26, DMSO); 1 H NMR (300 MHz, CDCl 3 ) δ 6.89 (s, 1H), 6.39 (s, 1H), 5.17 (s, br, 1H), 3.75-3.73 (m, 1H), 2.72-0.88 (m, 31H), 0.80 (s, 3H); 13 (1S,3aS,4aS,10aR,11aS)-2,3,3a,4,4a,5,10,10a,11,11a-Decahydro-11a-methyl-1H-cyclopent[b]anthracene-1,8-diol (5). DIBAL-H (20 mL, 1.0 M in toluene, 20 mmol) was slowly added to a solution of compound 37 (1.65 g, 5.77 mmol) in toluene (30 mL).…”

Section: General Methodsmentioning

confidence: 99%

“…We prepared analogues in six different ring systems (Fig. 2 benz[f]indenes (13)(14)(15)(16) and benz[e]indenes (17)(18)(19)(20); (3) indenes connected by a -(CH 2 ) nlinker to a phenol (21)(22)(23)(24); and (4) a spiro ring system (25,26). In all ring systems we prepared analogues with an adamantyl group ortho to the phenolic hydroxyl group to evaluate the impact of this substituent on neuroprotective activity.…”

Section: Introductionmentioning

confidence: 99%

“…18 Accordingly, indenone 29 was first carbomethoxylated with dimethyl carbonate to give enol 30 as described previously. 19,20 Benzylation then was carried out using a modified Yadav's method 21 to give compound 31. The NMR spectrum of compound 31 indicated that it was 5 : 1 mixture of diastereomers resulting from the new chiral center formed in the benzylation reaction.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Structure–activity studies of non-steroid analogues structurally-related to neuroprotective estrogens

et al. 2016

Self Cite

View full text Add to dashboard Cite

Estrone and 17β-estradiol are phenolic steroids that are known to be neuroprotective in multiple models of neuronal injury. Previous studies have identified the importance of their phenolic steroid A-ring for neuroprotection and have identified ortho substituents at the C-2 and C-4 positions on the phenol ring that enhance this activity. To investigate the importance of the steroid ring system for neuroprotective activity, phenolic compounds having the cyclopent[b]anthracene, cyclopenta[b]phenanthrene, benz[f]indene, benz[e]indene, indenes linked to a phenol, and a phenolic spiro ring system were prepared. New synthetic methods were developed to make some of the cyclopent[b]anthracene analogues as well as the spiro ring system. Compounds were evaluated for their ability to protect HT-22 hippocampal neurons from glutamate neurotoxicity and their activity relative to a potent neuroprotective analogue of 17β-estradiol was determined. An adamantyl substituent placed ortho to the phenolic hydroxyl group gave neuroprotective analogues in all ring systems studied.

show abstract

“…20 The adamantyl groups were then added to CP[ b ]Ps 9 and 10 to obtain compounds 11 and 12 , respectively.…”

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: General Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Structure–activity studies of non-steroid analogues structurally-related to neuroprotective estrogens

et al. 2016

Self Cite

View full text Add to dashboard Cite

show abstract

The Krapcho Dealkoxycarbonylation Reaction of Esters with α‐Electron‐Withdrawing Substituents

Krapcho

Ciganek

2013

Organic Reactions

View full text Add to dashboard Cite

The Krapcho reaction involves esters with α‐electron‐withdrawing substituents such as malonates, β‐keto esters, and α‐cyano esters, which undergo dealkoxycarbonylation on being heated in polar aprotic solvents (such as DMSO, DMF, or HMPT) in the presence of water, or in polar aprotic solvents with water in the presence of added salts (such as NaCN, NaCl, LiCl, LiI, or MgCl 2 ). This procedure avoids the use of strongly aqueous acidic and alkaline conditions and tolerates many functional and protecting groups. The chapter presents the mechanistic aspects of this procedure, which include reaction parameters such as solvents, salts, other additives, and the use of microwave irradiation. The diastereoselectivity of protonation of the enolate intermediate leading to the dealkoxycarbonylated products is discussed. Trapping of the intermediate enolate by electrophiles other than a proton is illustrated. Potential side reactions and same‐pot subsequent reactions of substrates are discussed along with functional‐group compatibility for halogens and nitrogen, oxygen, sulfur, selenium, and carbon functional groups. Several examples of applications of this methodology for the synthesis of natural products along with experimental conditions and procedures are presented. Closely related methods are discussed in the Comparison with Other Methods section. The tables, which consist of 371 pages, are grouped according to substrate structure. Selective entries for other methods (excluding classical aqueous acidic or basic methods) are included in the tabular survey for comparative purposes.

show abstract

Wacker Oxidation, The

2014

View full text Add to dashboard Cite

Terminal alkene substrates can be converted to methyl ketone products via a palladium‐catalyzed process known as the Wacker oxidation. This process has found widespread application in targeted synthesis, since alkene substrates are easily accessed and unreactive under diverse reaction conditions substrates and the resultant carbonyl products are common precursors for diverse synthetic manipulations. This chapter covers the application of the Wacker oxidation and variations of the Wacker oxidation to various types of alkene substrates. The literature covered spans the inception of the reaction in 1959 through November 2012. A discussion of the current mechanistic understanding is presented, emphasizing considerations that are relevant to synthetic application, including how the nature of the alkene substrate and nucleophiles other than water are proposed to influence the mechanistic pathways and ultimately the product distribution. The “Scope and Limitations” section is separated into discussions relating to functional group tolerance, the influence of heteroatoms proximal to the alkene substrate, and Wacker‐type oxidations that do not result in carbonyl products, such as cyclization reactions and aza‐Wacker reactions. Select applications of the Wacker oxidation in total synthesis are presented, as well as a comparison to other methods and examples of experimental conditions.

show abstract

The Efficient and Enantiospecific Total Synthesis of Cyclopenta[b]phenanthrenes Structurally‐Related to Neurosteroids

Cited by 6 publications

References 14 publications

Structure–activity studies of non-steroid analogues structurally-related to neuroprotective estrogens

Structure–activity studies of non-steroid analogues structurally-related to neuroprotective estrogens

The Krapcho Dealkoxycarbonylation Reaction of Esters with α‐Electron‐Withdrawing Substituents

Wacker Oxidation, The

Contact Info

Product

Resources

About