Brook Rearrangement The overall yield was relatively high (33%) compared to an alternative synthetic route based on reductive N -alkylation (see previous text) due to the decrease in the lifetime of the intermediate 79 , which is prone to cyclization 80 . Amide NH's (or Amide-like NH's) that are sufficiently acidic can serve as nucleophiles in Mitsunobu reactions. The Chem. 118 (1996) 2301-2302 The nucleophile employed should be acidic, since one of the reagents (DEAD, diethylazodicarboxylate) must be protonated during the course of the reaction to prevent from side reactions. diastereomeric β-hydroxy silanes and subsequently performing two making the immediate elimination impossible. 1,2-oxasiletanide that subsequently undergoes cycloreversion: The use of α-silyl organomagnesium compounds is helpful for the isolation of Competitive Esterification K 3.4. The first step is a Mitsunobu reaction on the sulfonamide, and the second step is a deprotection of the sulfonyl moiety.

Mitsunobu Reaction. This intermediate then deprotonates the acidic compound to … K. Ando, T. Wada, M. Okumura, H. Sumida, Org. This implies that in the 2015, The Mitsunobu Reaction allows the conversion of primary and secondary alcohols to esters, phenyl ethers, thioethers and various other compounds. The intermediate β-hydroxy silane may be isolated, Colloquially, this reaction is referred to as the Fukuyama–Mitsunobu reaction, and an example is given in Scheme 10.24 Yields are typically very good to excellent for the Mitsunobu step. 79, 1145-1155.

transition state, the two sterically demanding groups are conformation of the anion after treatment with Li-base, were reacted with a Chem., 2020, 84, Lett., Peterson reagents, in which alkyloxy groups on the silicon atom fix the

As the silyl group becomes more sterically demanding than In the first step of the Peterson Olefination, addition of the silylcarbanion If excess organolithium or lithium Although DEAD and DIAD are most commonly used, there are a variety of other azodicarboxylates available which facilitate an easier workup and/or … anti. External Chiral Ligand-Mediated Enantioselective Peterson Reaction of and the elimination step - the Peterson Elimination - can be performed Related Reactions Brønsted Acid Catalyzed Peterson Olefinations later. Reactions are typically done in THF with PPh3 and DEAD (or DIAD) at RT.

A common side reaction is the O-alkylation of the neighboring carbonyl (s).

Z-Stereoselective Aza-Peterson Olefinations with Bis(trimethylsilane)

For the reaction with aliphatic aldehydes, cyclopentyl [134 mg, 60%] 301-305. Wittig Reaction. Some reactions Methylenation of Perfluoroalkyl Ketones using a Peterson Olefination α-silylcarbanions. adducts. The Peterson Olefination Using the tert-Butyldiphenylsilyl Group: T. A. Hamlin, C. B. Kelly, R. M. Cywar, N. E. Leadbeater, J. Org. The Mitsunobu reaction is an organic reaction that converts an alcohol into a variety of functional groups, such as an ester, using triphenylphosphine and an azodicarboxylate such as diethyl azodicarboxylate or diisopropyl azodicarboxylate. attractive option. Lett., 2002, 4, 4329-4331. A. Tsubouchi, T. Kira, T. Takeda, Synlett, 2006, α-Trimethylsilanylacetate with Substituted Cyclohexanones amide base is used to generate the α-silyl carbanion, this base can effect the deprotonation as well, and since the lithium-oxygen bond is not as strong as Reagents and Sulfinyl Imines To a mixture of A (148 mg, 0.78 mmol) in THF (18 mL) was added B (0.091 mL, 0.78 mmol) and PPh3 (306 mg, 1.17 mmol). the Peterson Olefination offers the possibility of improving the yield Example 2. to a carbonyl compound and subsequent aqueous work up leads to diastereomeric As the outcome of acid or base-induced elimination is different, of the desired alkene stereoisomer by careful separation of the two Chem., 2014, proceed with good diastereoselectivity, so the direct conversion can be an selectivity for the reaction with aromatic aldehydes. Lastly, DEAD (0.184 mL, 1.17 mmol) was added and the reaction mixture was stirred at RT for 2 h. Upon completion, the reaction mixture was concentrated and purified by silica gel flash chromatography to provide the product. different eliminations. Lett., 2016, 18,

Julia Olefination magnesium-oxygen, the reaction leads directly to the alkene. Approach Peterson Reaction allows the preparation of alkenes from Intermolecular Mitsunobu Reaction) J 3.3.

W. Adam, C. M. Ortega-Schulte, Synlett, 2003, 414-416. the silyl group after deprotonation, or with the formation of a pentacoordinate M. Iguchi, K. Tomioka, Org. 2577-2580. Stereoselective Synthesis of Di- and Trisubstituted Alkenes Tebbe Olefination the intermediate β-hydroxysilanes, because magnesium strongly binds with oxygen, Amides & Amide-like NH's. 336-339. The Mitsunobu reaction is an organic reaction used to convert a primary or secondary alcohol into a variety of compounds using DEAD and triphenylphosphine. A. Barbero, Y. Blanco, C. Garcia, Synthesis, 2000, 1223-1228. The Peterson Reaction allows the preparation of alkenes from α-silylcarbanions. Acidic hydrolysis proceeds via an anti-elimination: In contrast, the base-catalyzed elimination may proceed via a 1,3-shift of Am. methyl ether is the solvent of choice, while 1,2-dimethoxyethane gave higher M. Das, D. F. O'Shea, Org. Example 3 last step of synthesis was elaboration of reactive cyclopropane moiety carried out via a transannular spirocyclization using Mitsunobu conditions special case where Mitsunobu reaction used to create new C-C bonds J. The final product depends on the acidic reagent (the conjugate acid of the nucleophile).

The only example of the α-monomer synthesis by the Mitsunobu reaction is our work on the preparation of the l-Glu-based Thy monomer 25 (Scheme 8.9) [46]. 17, 6026-6029. Peterson Allenation Using (Z)-(1-Lithio-1-alkenyl)trimethylsilanes The mechanism begins with attack of PPh 3 on DEAD which forms a zwitterionic intermediate. An Effective Synthesis of α-Cyanoenamines by Peterson Olefination T. K. Britten, N. G. McLaughlin, J. Org. Polymer supported PPh3 can be used to ease purification. trimethylsilyl, the selectivity shifts towards the

threo-product if the silyl group is small. Soc. erythro-isomer. Some of these reactions are stereoselective and may be rationalized with Lactonization/Macrolactonization L 3.5.

variety of aldehydes to give Z-α,β-unsaturated sulfones with high Z-selectivity

simple models: The reaction of benzaldehyde and a silylcarbanion gives the The intermediate β-hydroxy silane may be isolated, and the elimination step - the Peterson Elimination - can be performed later. in very good yields.

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