Diastereoselective schenck ene reaction of singlet oxygen with chiral allylic alcohols; access to enantiomerically enriched 1,2,4-trioxanes

Sabbani, Sunil; Pensée, Louise La; Bacsa, John; Hedenström, Erik

doi:10.1016/j.tet.2009.08.020

Cited by 17 publications

(13 citation statements)

References 30 publications

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“…25 Recently, this efficient synthetic approach was successfully used for the preparation of a series of chiral 1,2,4-trioxanes. 26 Scheme 1 Synthesis of 1,2,4-trioxane moiety via the 1 O 2 ene reaction…”

Section: Introductionmentioning

confidence: 99%

Recent Mechanistic Insights in the Singlet Oxygen Ene Reaction

Alberti¹,

Orfanopoulos²

2010

Synlett

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Singlet oxygen reacts with alkenes, which bear allylic hydrogens, in an ene fashion to afford allylic hydroperoxides. This reaction, apart from its synthetic usefulness, has received extensive mechanistic attention. Numerous experimental studies (e.g., trapping of intermediates, deuterium kinetic isotope effects, regio-or stereoselectivity studies etc.) and to a lesser extend computational work, support a stepwise mechanism with the formation of a threemembered ring (perepoxide-like) intermediate. This Account mainly highlights our group's earlier and recent experimental efforts to ascertain facts relating to this concept.

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Section: Introductionmentioning

confidence: 99%

Recent Mechanistic Insights in the Singlet Oxygen Ene Reaction

Alberti¹,

Orfanopoulos²

2010

Synlett

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“…In 2009, Sabani et al have reported the first diastereoselective ene reaction of singlet oxygen with enantiomericallyenriched chiral allylic alcohols. [41] The starting materials were synthesized by addition of organozinc reagents to α,β-unsaturated aldehydes using either (À ) or (+)-3-exomorpholinoisoborneol (MIB) as a catalyst (Scheme 13). [42] The desired chiral enantiomerically-enriched alcohols were obtained with 55-95 % yield and 90-98 % e.e.…”

Section: Photooxygenation Of Allyl Alcoholsmentioning

confidence: 99%

“…The synthesis of 1,2,4-trioxanes has also been carried out starting from enantiomerically enriched (R,R)-or (S,S)-threo-βhydroxy hydroperoxides. [41] These derivatives were reacted with a small range of cyclic ketones in the presence of p-toluene sulfonic acid to give enantioenriched 1,2,4-trioxanes in 16-78 % yield (Scheme 42). It should be noted that the minor diastereoisomer can be separated at that stage by column chromatography.…”

Section: Per(oxy)acetalization To 124-trioxanesmentioning

confidence: 99%

The Chemistry of β‐Hydroxy Hydroperoxides

Louvel

Miguel

et al. 2021

Eur J Org Chem

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β-Hydroxy hydroperoxides (β-hydroperoxy alcohols) are interesting chemical platforms, notably for the preparation of 1,2,4trioxanes, that are key features of numerous bioactive products such as artemisinin. In this review, the main synthetic methods to prepare β-hydroxy hydroperoxides are presented, such as the photooxidation of allylic alcohols with singlet oxygen and the ring-opening of epoxides with H 2 O 2 . The main applications of β-hydroxy hydroperoxides are also detailed, including their peracetalization to 1,2,4-trioxanes, their use as epoxidating agents and their fragmentation to carbonyl compounds. A final section is dedicated to the general characteristics and practical aspects of β-hydroxy hydroperoxides, including their stability, safety and characterization through spectroscopic means.

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“…Most common approaches are based on asymmetric reduction of enones ,, or enantioselelective addition to enals (Scheme ). , Other methods involve vinylation of aldehydes, − olefination of hydroxy aldehydes, , or by kinetic resolution processes . However, these methods lack generality and very often suffer from insufficient efficiency and stereoselectivity.…”

Section: Introductionmentioning

confidence: 99%

The Synthesis of Chiral β,β-Diaryl Allylic Alcohols and Their Use in the Preparation of α-Tertiary Allylamines and Quaternary α-Amino Acids

2017

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An approach to nonracemic β,β-diarylsubstituted allyl alcohols is described. Their synthesis starts from l-lactic acid-derived propargyl alcohol, which is submitted to sequential Sonogashira/Suzuki or Sonagashira/Stille coupling reactions. Both approaches enable the synthesis of either (Z)- or (E)-allylic alcohols regarding the order of introducing coupling agents. The obtained allyl alcohols were applied in the synthesis of nonracemic α-tertiary allylamines via stereocontrolled cyanate-to-isocyanate sigmatropic rearrangement reactions of the corresponding allyl carbamates. The stereoselectivity of the process is controlled by the geometry of the double bond of the starting allyl derivative. As demonstrated, a rearrangement of (S,Z)-allyl carbamates provides (S)-teriary allylamines, whereas the transformation (S,E)-isomers leads to (R)-allylamines.

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Diastereoselective schenck ene reaction of singlet oxygen with chiral allylic alcohols; access to enantiomerically enriched 1,2,4-trioxanes

Cited by 17 publications

References 30 publications

Recent Mechanistic Insights in the Singlet Oxygen Ene Reaction

Recent Mechanistic Insights in the Singlet Oxygen Ene Reaction

The Chemistry of β‐Hydroxy Hydroperoxides

The Synthesis of Chiral β,β-Diaryl Allylic Alcohols and Their Use in the Preparation of α-Tertiary Allylamines and Quaternary α-Amino Acids

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