Selective Mono‐ and 1,2‐Difunctionalisation of Cyclopentene Derivatives via Mg and Cu Intermediates

We report a short and convenient synthesis of two configurationally locked retinals that are important for applications in the context of optogenetics. The C11–C15 cyclopentyl fragments of both retinals were obtained by palladium‐catalysed alkoxycarbonylation and merged with the rest of the carbon skeleton through Wittig olefination. The preparation of the required and known ylide precursor was revisited and optimised. This synthetic route enables gram‐scale preparation of both retinal derivatives.

show abstract

“…IR: $\tilde {\nu}$ = 3330 (w), 1670 (s), 1605 (s), 1430 (w) cm –1 . The 1 H, 13 C NMR, EI‐MS and IR data match reported values 29,30…”

Section: Methodssupporting

confidence: 80%

Short, Convergent Synthesis of Locked Retinals

Andrä

Tzschucke

2014

Eur J Org Chem

View full text Add to dashboard Cite

show abstract

“…The sought after diol precursor (not shown in Scheme 5.6) is produced, which in turn yields the substituted rubrene when treated with hydrogen iodide [136]. When 1,2-dibromocyclopent-1-ene is reacted with 83, only a single magnesium-bromine exchange takes place [137]. It was discovered that THF solutions of the new magnesium complex are extremely stable under argon, and there is no evidence to suggest that salt elimination of MgClBr takes place.…”

Section: Synthetic Applications Of Lithium Magnesiates: Turbo-grignarmentioning

confidence: 99%

Mixed Lithium Complexes: Structure and Applicationin Synthesis

Mulvey

O’Hara

2014

Lithium Compounds in Organic Synthesis

View full text Add to dashboard Cite

IntroductionFor half a century, organolithium (C-Li bonded) reagents and lithium amides (N-Li bonded) have played a pivotal role in the development of modern day synthetic chemistry. Reagents in these categories, in particular the butyllithiums (the normal-, secondary-, and tertiary-isomers), lithium diisopropylamide (LDA), lithium 2,2,6,6-tetramethylpiperid-1-ide (LiTMP), and lithium 1,1,1,3,3,3-hexamethyldisilazide (LiHMDS) are utilized in most synthetic laboratories around the world and are especially important in the metallation reaction (that is, the conversion of a relatively inert C-H bond into a more reactive (more chemically pliable) C-Li bond) and in the kinetically operative metal-halogen exchange reactions. The past two decades have witnessed several new classes of constitutionally more complex reagents that contain multimetal and/or multianion formulations that have challenged the dominance of these unimetallic/unianionic reagents in deprotonative/metal-halogen exchange chemistry. This chapter covers some of the rich structural and synthetic chemistry of these new and still emerging systems, detailing only a small selection of what these classes of compounds can offer the chemist at the present time. Structural Chemistry of Heterometallic Lithium ComplexesStructure is inextricably and mutually linked to reactivity; hence, much recent research activity has focused on the elucidation of solid-state and solution structures of lithium organometallics and amides. This section concentrates on the structural chemistry of lithium-containing mixed-metal complexes, focusing particularly on mixed s-block (Group 1/Group 1 or Group 1/Group 2) complexes, and those containing the Group 12 d 10 metal zinc, which is commonly regarded as a displaced alkaline earth metal. In recent years, heterometallic sodium reagents (particularly sodium zincates, magnesiates, aluminates, etc.) have received a great Lithium Compounds in Organic Synthesis: From Fundamentals to Applications, First Edition. Edited by Renzo Luisi and Vito Capriati.

show abstract

“…[14] Initial attempts to use 1 in a Sonogashira cross-coupling reaction [15] with trimethylsilylacetylene (TMSA) were surprisingly unsuccessful. Thus, vinyl bromide 2 was converted to vinyl stannane 3 and then vinyl iodide 4 using a protocol developed by Knochel et al [17] Vinyl iodide 4 readily reacted with TMSA or TIPSA under Pd catalysis to provide 5 a (78 %) and 5 b (86 %) in good yield. Attempted cross-coupling of 2 with either TMSA or triisopropylsilylacetylene (TIPSA) under either Sonogashira or Negishi conditions offered only traces of the desired enediyne product.…”

mentioning

confidence: 99%

Optically Pure, Monodisperse cis‐Oligodiacetylenes: Aggregation‐Induced Chirality Enhancement

Chernick¹,

Borzsonyi²,

Steiner³

et al. 2013

Angew Chem Int Ed

View full text Add to dashboard Cite

Conformational changes in the conjugated backbone of poly- and oligodiacetylenes (PDAs and ODAs) play an important role in determining the electronic properties of these compounds. At the same time, conformational changes can also result in a folded structure that shows helical chirality. Using d-camphor as a chiral building block, we have designed a high-yielding, iterative synthesis of monodisperse, optically pure cis-oligodiacetylenes (ODAs). cis-ODAs up to the tridecamer have been formed, which is the longest monodisperse cis-ODA reported to date. UV/Vis spectroscopy suggests a large effective conjugation length in THF, likely the result of a linear, planar conformation in this solvent. High-resolution STM/AFM measurements of the nonamer cast from THF onto HOPG show a linear structure. In iPrOH, circular dichroism (CD) spectra suggest the formation of chiral aggregates for ODAs with at least nine d-camphor units, based on a strong CD response.

show abstract

Selective Mono‐ and 1,2‐Difunctionalisation of Cyclopentene Derivatives via Mg and Cu Intermediates

Cited by 36 publications

References 57 publications

Short, Convergent Synthesis of Locked Retinals

Short, Convergent Synthesis of Locked Retinals

Mixed Lithium Complexes: Structure and Applicationin Synthesis

Optically Pure, Monodisperse cis‐Oligodiacetylenes: Aggregation‐Induced Chirality Enhancement

Contact Info

Product

Resources

About