Through-bond interaction via cyclobutane relay orbitals as a means of extending conjugation.  Synthesis of tricyclo[5.5.0.02,8]dodecatetraene, tricyclo[5.3.0.02,8]deca-3,5,9-triene, and 9,10-dimethylenetricyclo[5.3.0.02,8]deca-3,5-diene

Dressel, Juergen.; Chasey, Kent L.; Paquette, Leo A.

doi:10.1021/ja00224a036

Cited by 25 publications

(6 citation statements)

References 1 publication

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“…The tricyclodecadiene 90 has also been synthesized for the study of the through-space interaction of two π systems, located perpendicular to each other. 222 These results demonstrate that this process is effective for the construction of medium rings with strained structures.…”

Section: Synthesis Of Ring Compounds With Unique Structuresmentioning

confidence: 74%

The McMurry Coupling and Related Reactions

Takeda

Tsubouchi

2013

Organic Reactions

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The McMurry coupling reaction has been recognized as one of the most efficient methods for the synthesis of alkenes from carbonyl compounds. This reaction can be applied to the preparation of various alkenes that are otherwise difficult to prepare. For example, sterically congested tetrasubstituted alkenes as well as medium to large membered rings involving natural products may be accessed via this process. This coupling utilizes various low‐valent titanium reagents generated by the reduction of titanium (III or IV) chloride with K, Zn, LiAlH 4 , C 8 K, amongst others. Furthermore, a variety of low‐valent metal species other than titanium, including aluminum, zirconium, niobium, molybdenum, indium, tungsten, and samarium, have also been found to promote the reductive coupling of carbonyl compounds. The scope and limitations of these reagent systems are reviewed in this chapter, together with the stereochemistry and reaction mechanism. This reaction is categorized into four coupling modes: i) homocoupling giving symmetrical alkenes, ii) mixed coupling giving unsymmetrical alkenes, iii) intramolecular coupling giving cycloalkenes, and iv) tandem coupling giving cyclic polyenes. Characteristics of these reaction modes are described briefly. A selection of synthetic applications are reviewed, including examples of the preparation of sterically congested and strained alkenes, medium to large‐ring compounds, biologically active targets, as well as substrates applicable in material science. Experimental conditions used for this versatile process are summarized to assist the choice of suitable conditions.

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Section: Synthesis Of Ring Compounds With Unique Structuresmentioning

confidence: 74%

The McMurry Coupling and Related Reactions

Takeda

Tsubouchi

2013

Organic Reactions

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“…However, on larger scale, removal of the reaction by‐products from 23 , either by column chromatography or Nussbaumer et al.’s modified work‐up, [23] proved difficult. Furthermore, we observed the partial conversion of the thiono group in both 21 and 22 to a carbonyl upon silica gel chromatography (see Supporting Information) [24] . One solution to avoid silica gel was to recrystallise acetal 22 , giving a 72 % yield over two steps from alcohol 16 .…”

Section: Resultsmentioning

confidence: 94%

“…Asymmetric synthesis of trans-hydrindanone 24 Hajos-Parrish ketone 15 was prepared in two steps from commercially available 2-methylcyclopentan-1,3-dione in > 98 % ee and on > 100 g scale using the proline-catalysed aldol reaction under the conditions initially reported by Hajos and Parrish (Scheme 4). [14] Selective deoxygenation of the nonconjugated ketone in 15 has not been previously reported, although chemo-and stereoselective reduction to alcohol 16 is well known; [15] thus we elected to investigate a radical-mediated deoxygenation approach.…”

Section: Resultsmentioning

confidence: 99%

Studies towards the Synthesis of (+)‐Dictyoxetane

Benford-Ward

Ahmadipour

Sembayeva

et al. 2022

Chemistry A European J

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The dolabellane‐type diterpene dictyoxetane represents a significant challenge to synthetic organic chemistry. Methodology directed towards the total synthesis of naturally occurring (+)‐dictyoxetane is reported. Catalytic asymmetric synthesis of the trans‐hydrindane ring system is achieved through chemoselective deoxygenation of the Hajos‐Parrish ketone. An alternative to the Garst‐Spencer furan annulation is developed for the synthesis of a 2,5‐dimethyl, tetrasubstituted furan, employing a tandem 5‐exo‐dig alcohol to alkyne cyclisation/aromatisation reaction as a key step. The (4+3) cycloaddition reaction of an oxyallyl cation with a tetrasubstituted furan is established on a cyclohexanone‐derived model system, and a range of related (4+3) cycloadditions investigated on a homochiral, trans‐hydrindane‐fused furan, where regio‐ and diastereoselectivity is required for the natural product synthesis. In an alternative (4+2) Diels‐Alder approach, a C2‐symmetric vinyl sulfoxide‐based chiral ketene equivalent is used to prepare oxanorbornenes with the same oxygen bridge stereochemistry found in the 2,7‐dioxatricyclo[4.2.1.03,8]nonane ring system of the natural product.

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“…However, there will be additional nodal planes due to the extra s-bonds (Figure S11 and S12). 10,11,42 The electrohelicity effect thus appears to be less pronounced in larger systems. In summary, we have explored how helical p-conjugation between the perpendicular p-systems of allene and spiropentadiene affect their electronic transitions and the helicity thereof.…”

Section: Please Do Not Adjust Marginsmentioning

confidence: 99%

Helical Electronic Transitions of Spiroconjugated Molecules

Garner

Corminbœuf²

2021

Preprint

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<div><div><div><div><p>The two pi-systems of allene can mix into helical molecular orbitals (MOs), yet the helicity is lost in the pi-pi∗ transitions. In spiroconjugated molecules the relative orientation of the two π- systems is different as only half the pi-MOs become helical. Consequently, the helicity of the electronic transitions is symmetry protected and thus helical pi-conjugation can manifest in observable electronic and chiroptical properties.</p></div></div></div></div>

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Through-bond interaction via cyclobutane relay orbitals as a means of extending conjugation. Synthesis of tricyclo[5.5.0.02,8]dodecatetraene, tricyclo[5.3.0.02,8]deca-3,5,9-triene, and 9,10-dimethylenetricyclo[5.3.0.02,8]deca-3,5-diene

Cited by 25 publications

References 1 publication

The McMurry Coupling and Related Reactions

The McMurry Coupling and Related Reactions

Studies towards the Synthesis of (+)‐Dictyoxetane

Helical Electronic Transitions of Spiroconjugated Molecules

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