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- https://chem.libretexts.org/Bookshelves/Organic_Chemistry/Organic_Chemistry_III_(Morsch_et_al.)/29%3A_Orbitals_and_Organic_Chemistry_-_Pericyclic_Reactions/29.08%3A_Some_Examples_of_Sigmatropic_RearrangementsA sigmatropic rearrangement which involves a [1,5] hydrogen shift, like the one shown below illustrates, a hydrogen atom (s orbital) moving across a 5 atom system containing two conjugated double bond...A sigmatropic rearrangement which involves a [1,5] hydrogen shift, like the one shown below illustrates, a hydrogen atom (s orbital) moving across a 5 atom system containing two conjugated double bonds. The suprafacial nature of this reaction comes from the orbital symmetry of the HOMO from a 6 pi electron molecular orbital. During the reaction mechanism the hydrogen atom, an s orbital, is passes from one molecular to another of the same sign on the same side of the molecule or suprafacial.
- https://chem.libretexts.org/Courses/can/CHEM_232_-_Organic_Chemistry_II_(Puenzo)/15%3A_Orbitals_and_Organic_Chemistry_-_Pericyclic_Reactions/15.09%3A_Some_Examples_of_Sigmatropic_RearrangementsA sigmatropic rearrangement which involves a [1,5] hydrogen shift, like the one shown below illustrates, a hydrogen atom (s orbital) moving across a 5 atom system containing two conjugated double bond...A sigmatropic rearrangement which involves a [1,5] hydrogen shift, like the one shown below illustrates, a hydrogen atom (s orbital) moving across a 5 atom system containing two conjugated double bonds. The suprafacial nature of this reaction comes from the orbital symmetry of the HOMO from a 6 pi electron molecular orbital. During the reaction mechanism the hydrogen atom, an s orbital, is passes from one molecular to another of the same sign on the same side of the molecule or suprafacial.
- https://chem.libretexts.org/Workbench/LCDS_Organic_Chemistry_OER_Textbook_-_Todd_Trout/30%3A_Orbitals_and_Organic_Chemistry_-_Pericyclic_Reactions/30.09%3A_Some_Examples_of_Sigmatropic_RearrangementsTwo other important sigmatropic reactions are the Claisen rearrangement of either an allyl aryl ether ( H 2 C ═ CHCH 2 ─ O ─ Ar H 2 C ═ CHCH 2 ─ O ─ Ar ) or an allyl vinyl ( H 2 C ═ CHCH 2 ─ O ─ CH ═ ...Two other important sigmatropic reactions are the Claisen rearrangement of either an allyl aryl ether ( H 2 C ═ CHCH 2 ─ O ─ Ar H 2 C ═ CHCH 2 ─ O ─ Ar ) or an allyl vinyl ( H 2 C ═ CHCH 2 ─ O ─ CH ═ CH 2 H 2 C ═ CHCH 2 ─ O ─ CH ═ CH 2 ) ether, and the Cope rearrangement of a 1,5 hexadiene to an isomeric 1,5-diene.
- https://chem.libretexts.org/Bookshelves/Organic_Chemistry/Basic_Principles_of_Organic_Chemistry_(Roberts_and_Caserio)/26%3A_More_on_Aromatic_Compounds/26.01%3A_Aryl_Oxygen_CompoundsPhenols are enols, and enols normally are unstable with respect to the corresponding carbonyl compounds. The situation is different for phenols because of the inclusion of the carbon-carbon double bon...Phenols are enols, and enols normally are unstable with respect to the corresponding carbonyl compounds. The situation is different for phenols because of the inclusion of the carbon-carbon double bond into the aromatic ring and the associated aromatic stabilization. Phenol (benzenol) exists exclusively in the enol form. In general, phenols are somewhat more polar than the corresponding saturated alcohols.
- https://chem.libretexts.org/Courses/Smith_College/Organic_Chemistry_(LibreTexts)/29%3A_Orbitals_and_Organic_Chemistry_-_Pericyclic_Reactions/29.08%3A_Some_Examples_of_Sigmatropic_RearrangementsA sigmatropic rearrangement which involves a [1,5] hydrogen shift, like the one shown below illustrates, a hydrogen atom (s orbital) moving across a 5 atom system containing two conjugated double bond...A sigmatropic rearrangement which involves a [1,5] hydrogen shift, like the one shown below illustrates, a hydrogen atom (s orbital) moving across a 5 atom system containing two conjugated double bonds. The suprafacial nature of this reaction comes from the orbital symmetry of the HOMO from a 6 pi electron molecular orbital. During the reaction mechanism the hydrogen atom, an s orbital, is passes from one molecular to another of the same sign on the same side of the molecule or suprafacial.
- https://chem.libretexts.org/Courses/Martin_Luther_College/Organic_Chemistry_-_MLC/03%3A_Alcohols_Ethers_Thiols_Sulfides_and_Amines/3.02%3A_Ethers_and_Epoxides_Thiols_and_Sulfides/3.2.05%3A_Reactions_of_Ethers-_Claisen_RearrangementThe Claisen rearrangement takes place through a concerted mechanism in which a C-C bond forms between the C3 of the allyl group and the ortho position of the benzene ring at the same time that the C-O...The Claisen rearrangement takes place through a concerted mechanism in which a C-C bond forms between the C3 of the allyl group and the ortho position of the benzene ring at the same time that the C-O bond of the ether breaks. The Claisen rearrangement is part of a broader class of reactions called sigmatropic rearrangements which will be discussed in more detail in Section 30-8.
- https://chem.libretexts.org/Bookshelves/Organic_Chemistry/Organic_Chemistry_(OpenStax)/30%3A_Orbitals_and_Organic_Chemistry_-_Pericyclic_Reactions/30.08%3A_Some_Examples_of_Sigmatropic_RearrangementsThis section covers sigmatropic rearrangements, a type of pericyclic reaction where sigma bonds break and reform while the molecular structure rearranges. The examples illustrate the mechanisms and st...This section covers sigmatropic rearrangements, a type of pericyclic reaction where sigma bonds break and reform while the molecular structure rearranges. The examples illustrate the mechanisms and stereochemical outcomes of various rearrangements, such as the [3,3]-sigmatropic rearrangement. The discussion highlights the significance of orbital symmetry and how these reactions can occur in a concerted fashion.
- https://chem.libretexts.org/Courses/Smith_College/CHM_223_Chemistry_III%3A_Organic_Chemistry_(2024)/03%3A_Ethers_and_Epoxides_Thiols_and_Sulfides/3.05%3A_Reactions_of_Ethers-_Claisen_Rearrangement_(reference_only_covered_in_CHM_321)The Claisen rearrangement takes place through a concerted mechanism in which a C-C bond forms between the C3 of the allyl group and the ortho position of the benzene ring at the same time that the C-O...The Claisen rearrangement takes place through a concerted mechanism in which a C-C bond forms between the C3 of the allyl group and the ortho position of the benzene ring at the same time that the C-O bond of the ether breaks. The Claisen rearrangement is part of a broader class of reactions called sigmatropic rearrangements which will be discussed in more detail in Section 30-8.
- https://chem.libretexts.org/Bookshelves/Organic_Chemistry/Organic_Synthesis_(Shea)/01%3A_Pericyclic_Reactions/1.04%3A_Sigmatropic_RearrangementsThis chapter highlights synthetically useful sigmatropic rearrangements including hydride shifts, the Cope rearrangement, the Claisen rearrangement, and the Wittig rearrangement.
- https://chem.libretexts.org/Bookshelves/Organic_Chemistry/Organic_Chemistry_(Morsch_et_al.)/18%3A_Ethers_and_Epoxides_Thiols_and_Sulfides/18.04%3A_Reactions_of_Ethers_-_Claisen_RearrangementThe Claisen rearrangement is a key organic reaction that involves the thermal rearrangement of allyl vinyl ethers to form β-aryl allyl ethers. It's a valuable tool in organic synthesis, enabling the c...The Claisen rearrangement is a key organic reaction that involves the thermal rearrangement of allyl vinyl ethers to form β-aryl allyl ethers. It's a valuable tool in organic synthesis, enabling the creation of complex molecular structures with high selectivity and efficiency.
- https://chem.libretexts.org/Bookshelves/Organic_Chemistry/Organic_Chemistry_(OpenStax)/18%3A_Ethers_and_Epoxides_Thiols_and_Sulfides/18.11%3A_SummaryThe cleavage reaction takes place by an S N 2 mechanism at the less highly substituted site if only primary and secondary alkyl groups are bonded to the ether oxygen, but by an S N 1 or E1 mechanism i...The cleavage reaction takes place by an S N 2 mechanism at the less highly substituted site if only primary and secondary alkyl groups are bonded to the ether oxygen, but by an S N 1 or E1 mechanism if one of the alkyl groups bonded to oxygen is tertiary. Cleavage of the C–O bond at the less highly substituted site occurs if both epoxide carbons are primary or secondary, but cleavage of the C–O bond to the more highly substituted site occurs if one of the epoxide carbons is tertiary.
