Tetrakis (1-methylcyclopropyl) ethylene in four steps from α-methyl-γ-butyrolactone

Böhrer, Gerald; Knorr, Rudolf

doi:10.1016/0040-4039(84)80102-1

Cited by 18 publications

(10 citation statements)

References 13 publications

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“…For example, the homocoupling of cyclopropyl aldehydes and ketones furnishes alkenes bearing cyclopropyl rings 46 43 and 47. 183,184 The dicyclobutyl ketone can be employed for the mixedcoupling the acetophenones to produce the dicyclobutylethenes 48. Similarly, benzocyclobutanones afford the bi(cyclobutylidenes) 50 as (E)/(Z) mixtures.…”

Section: Synthesis Of Sterically Hindered And/or Strained Alkenesmentioning

confidence: 99%

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 Sterically Hindered And/or Strained Alkenesmentioning

confidence: 99%

The McMurry Coupling and Related Reactions

Takeda

Tsubouchi

2013

Organic Reactions

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“…Cyclopropyl-substituted ethenes can also efficiently be prepared by reductive dimerization (McMurry coupling) of cyclopropylketones. Applying different methods to generate the low-valent titanium species, several groups synthesized 1,1- and 1,2-dicyclopropyl- as well as tetracyclopropylethenes. − …”

Section: Branched Aggregates Of Three-membered Ringsmentioning

confidence: 99%

Three-Membered-Ring-Based Molecular Architectures

2006

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“…With the TiCl 4 -Zn system, the E=Z ratio in the coupling of aliphatic methyl alkyl ketones RCOMe varies with the steric bulk of the R group, ranging from 3:1 for R ¼ nPr to more than 200:1 for R ¼ tBu [12]. While the synthesis of 3 represents the coupling of a ''tied-back'' di-tert-butyl ketone [13], the preparation of the long sought-after tetra-tert-butylethylene has hitherto remained unsuccessful. The rotational barriers of the isopropyl and cyclohexyl groups in 1 and 2 are equal to 16 and 18.7 kcal mol À1 , respectively [14,15], and it has been estimated that olefins with a strain energy lower than 19 kcal mol À1 may be synthesized by means of the McMurry reaction.…”

Section: Intermolecular Coupling Of Aldehydes and Ketonesmentioning

confidence: 99%