The Experts below are selected from a list of 867 Experts worldwide ranked by ideXlab platform
Yutaka Ukaji - One of the best experts on this subject based on the ideXlab platform.
-
z selective enol triflation of α alkoxyacetoaldehydes application to synthesis of z allylic alcohols via cross coupling reaction and 1 2 Wittig Rearrangement
Journal of Organic Chemistry, 2015Co-Authors: Fumiya Kurosawa, Takahiro Soeta, Takeo Nakano, Kohei Endo, Yutaka UkajiAbstract:The stereoselective transformation of α-alkoxyacetoaldehydes to the corresponding (Z)-vinyl triflates was achieved by treatment with phenyl triflimide and DBU. The stereochemistry was explained by the “syn-effect,” which was attributed primarily to an σ → π* interaction. The β-alkoxy vinyl triflates obtained were applied to the stereoselective synthesis of structurally diverse (Z)-allylic alcohols via transition metal-catalyzed cross-coupling reaction and [1,2]-Wittig Rearrangement.
-
(Z)‑Selective Enol Triflation of α‑Alkoxyacetoaldehydes: Application to Synthesis of (Z)‑Allylic Alcohols via Cross-Coupling Reaction and [1,2]-Wittig Rearrangement
2015Co-Authors: Fumiya Kurosawa, Takahiro Soeta, Takeo Nakano, Kohei Endo, Yutaka UkajiAbstract:The stereoselective transformation of α-alkoxyacetoaldehydes to the corresponding (Z)-vinyl triflates was achieved by treatment with phenyl triflimide and DBU. The stereochemistry was explained by the “syn-effect,” which was attributed primarily to an σ → π* interaction. The β-alkoxy vinyl triflates obtained were applied to the stereoselective synthesis of structurally diverse (Z)-allylic alcohols via transition metal-catalyzed cross-coupling reaction and [1,2]-Wittig Rearrangement
-
stereoselective synthesis of 2 z 4 e 2 4 pentadien 1 ols via sequential 1 4 elimination reaction and 1 2 Wittig Rearrangement starting from e 4 alkoxy 2 butenyl benzoates
Journal of Organic Chemistry, 2013Co-Authors: Takeo Nakano, Katsuhiko Inomata, Takahiro Soeta, Kohei Endo, Yutaka UkajiAbstract:The sequential 1,4-elimination reaction of (E)-4-alkoxy-2-butenyl benzoates and [1,2]-Wittig Rearrangement gave (2Z,4E)-2,4-pentadien-1-ols stereoselectively. Z-Selective formation of intermediary vinyl ethers, whose stereochemistry was well elucidated by the “syn-effect”, was achieved by treatment of the 2-butenyl benzoates with KOH in the presence of Pd catalyst. The subsequent [1,2]-Wittg Rearrangement by use of n-BuLi proceeded with retention of the stereochemistry of the intermediary vinyl ethers.
-
Stereoselective Synthesis of (2Z,4E)‑2,4-Pentadien-1-ols via Sequential 1,4-Elimination Reaction and [1,2]-Wittig Rearrangement Starting from (E)‑4-Alkoxy-2-butenyl Benzoates
2013Co-Authors: Takeo Nakano, Katsuhiko Inomata, Takahiro Soeta, Kohei Endo, Yutaka UkajiAbstract:The sequential 1,4-elimination reaction of (E)-4-alkoxy-2-butenyl benzoates and [1,2]-Wittig Rearrangement gave (2Z,4E)-2,4-pentadien-1-ols stereoselectively. Z-Selective formation of intermediary vinyl ethers, whose stereochemistry was well elucidated by the “syn-effect”, was achieved by treatment of the 2-butenyl benzoates with KOH in the presence of Pd catalyst. The subsequent [1,2]-Wittg Rearrangement by use of n-BuLi proceeded with retention of the stereochemistry of the intermediary vinyl ethers
-
syn effect in the 1 4 eliminative ring opening of 3 substituted e 1 propenyl oxiranes to the corresponding 2 4 dienyl alcohols
Chemistry Letters, 2005Co-Authors: Naohiro Takeda, Yutaka Ukaji, Takuya Chayama, Hiroyuki Takenaka, Katsuhiko InomataAbstract:Stereochemistry of the 1,4-climinative ring opening of [3-substituted (E)-1-propenyl]oxiranes to the corresponding 2,4-dienyl alcohols by LDA was investigated. The Z/E ratios of the resulting 2,4-dienyl alcohols varied with the substituents at 3-position of the propenyl group. This phenomenon was discussed based on the concept of a "syn-effect," which is most primarily rationalized by a σ → π* interaction. Furthermore, in the case of δ-benzyloxy-substituted vinyloxirane, [1,2]-Wittig Rearrangement proceeded following the initial 1,4-eliminative ring opening to give a (E,Z)-2,4-dienyl 1,6-diol in a completely stereoselective manner.
John P Wolfe - One of the best experts on this subject based on the ideXlab platform.
-
aza Wittig Rearrangements of n benzyl and n allyl glycine methyl esters discovery of a surprising cascade aza Wittig Rearrangement hydroboration reaction
ChemInform, 2016Co-Authors: Renata K Everett, John P WolfeAbstract:A new aza-[1,2]-Wittig Rearrangement of N-aryl-N-benzyl glycine methyl esters involving a rare benzyl group migration is developed.
-
aza Wittig Rearrangements of n benzyl and n allyl glycine methyl esters discovery of a surprising cascade aza Wittig Rearrangement hydroboration reaction
Journal of Organic Chemistry, 2015Co-Authors: Renata K Evere, John P WolfeAbstract:Treatment of N-(arylmethyl)-N-aryl or N-allyl-N-aryl glycine methyl ester derivatives with nBu2BOTf and iPr2NEt effects an aza-Wittig Rearrangement that provides N-aryl phenylalanine methyl ester derivatives and N-aryl allylglycine methyl ester derivatives, respectively, in good yield with moderate to good diastereoselectivity. Under similar conditions, analogous substrates bearing N-carbonyl groups are converted to 1,4,2-oxazaborole derivatives. Additionally, N-allyl-N-aryl glycine methyl ester derivatives subjected to similar conditions at elevated temperatures undergo an aza-[2,3]-Wittig Rearrangement, followed by a subsequent hydroboration oxidation reaction, to afford substituted amino alcohol products.
-
aza 1 2 Wittig Rearrangements of n benzyl glycine methyl esters a new approach to the synthesis of n aryl phenylalanine derivatives
Tetrahedron Letters, 2015Co-Authors: Renata K Evere, John P WolfeAbstract:Treatment of N-(arylmethyl)-N-aryl glycine methyl ester derivatives with Bu2BOTf and iPr2NEt effects an aza-[1,2]-Wittig Rearrangement that provides N-aryl phenylalanine methyl esters in good yields. Analogous substrates bearing N-carbonyl groups are converted to 1,4,2-oxazaborole derivatives under similar conditions.
-
Synthesis of Substituted 3‑Hydroxy-2-Furanone Derivatives via an Unusual Enolate Wittig Rearrangement/Alkylative Cyclization Sequence
2013Co-Authors: Renata K Everett, John P WolfeAbstract:Treatment of methyl O-(alkynylmethyl) glycolate derivatives with dialkylboron triflates and Hünig’s base leads to the formation of highly substituted 3-hydroxy-2-furanone derivatives. The transformations appear to proceed via an unusual mechanism involving initial 2,3-Wittig Rearrangement of a boron ester enolate followed by an alkylative cyclization reaction that leads to incorporation of an alkyl group from the boron reagent into the product
Takeo Nakano - One of the best experts on this subject based on the ideXlab platform.
-
z selective enol triflation of α alkoxyacetoaldehydes application to synthesis of z allylic alcohols via cross coupling reaction and 1 2 Wittig Rearrangement
Journal of Organic Chemistry, 2015Co-Authors: Fumiya Kurosawa, Takahiro Soeta, Takeo Nakano, Kohei Endo, Yutaka UkajiAbstract:The stereoselective transformation of α-alkoxyacetoaldehydes to the corresponding (Z)-vinyl triflates was achieved by treatment with phenyl triflimide and DBU. The stereochemistry was explained by the “syn-effect,” which was attributed primarily to an σ → π* interaction. The β-alkoxy vinyl triflates obtained were applied to the stereoselective synthesis of structurally diverse (Z)-allylic alcohols via transition metal-catalyzed cross-coupling reaction and [1,2]-Wittig Rearrangement.
-
(Z)‑Selective Enol Triflation of α‑Alkoxyacetoaldehydes: Application to Synthesis of (Z)‑Allylic Alcohols via Cross-Coupling Reaction and [1,2]-Wittig Rearrangement
2015Co-Authors: Fumiya Kurosawa, Takahiro Soeta, Takeo Nakano, Kohei Endo, Yutaka UkajiAbstract:The stereoselective transformation of α-alkoxyacetoaldehydes to the corresponding (Z)-vinyl triflates was achieved by treatment with phenyl triflimide and DBU. The stereochemistry was explained by the “syn-effect,” which was attributed primarily to an σ → π* interaction. The β-alkoxy vinyl triflates obtained were applied to the stereoselective synthesis of structurally diverse (Z)-allylic alcohols via transition metal-catalyzed cross-coupling reaction and [1,2]-Wittig Rearrangement
-
stereoselective synthesis of 2 z 4 e 2 4 pentadien 1 ols via sequential 1 4 elimination reaction and 1 2 Wittig Rearrangement starting from e 4 alkoxy 2 butenyl benzoates
Journal of Organic Chemistry, 2013Co-Authors: Takeo Nakano, Katsuhiko Inomata, Takahiro Soeta, Kohei Endo, Yutaka UkajiAbstract:The sequential 1,4-elimination reaction of (E)-4-alkoxy-2-butenyl benzoates and [1,2]-Wittig Rearrangement gave (2Z,4E)-2,4-pentadien-1-ols stereoselectively. Z-Selective formation of intermediary vinyl ethers, whose stereochemistry was well elucidated by the “syn-effect”, was achieved by treatment of the 2-butenyl benzoates with KOH in the presence of Pd catalyst. The subsequent [1,2]-Wittg Rearrangement by use of n-BuLi proceeded with retention of the stereochemistry of the intermediary vinyl ethers.
-
Stereoselective Synthesis of (2Z,4E)‑2,4-Pentadien-1-ols via Sequential 1,4-Elimination Reaction and [1,2]-Wittig Rearrangement Starting from (E)‑4-Alkoxy-2-butenyl Benzoates
2013Co-Authors: Takeo Nakano, Katsuhiko Inomata, Takahiro Soeta, Kohei Endo, Yutaka UkajiAbstract:The sequential 1,4-elimination reaction of (E)-4-alkoxy-2-butenyl benzoates and [1,2]-Wittig Rearrangement gave (2Z,4E)-2,4-pentadien-1-ols stereoselectively. Z-Selective formation of intermediary vinyl ethers, whose stereochemistry was well elucidated by the “syn-effect”, was achieved by treatment of the 2-butenyl benzoates with KOH in the presence of Pd catalyst. The subsequent [1,2]-Wittg Rearrangement by use of n-BuLi proceeded with retention of the stereochemistry of the intermediary vinyl ethers
Takayuki Oritani - One of the best experts on this subject based on the ideXlab platform.
-
first synthesis of pyricuol a plant pathogen isolated from rice blast disease fungus magnaporthe grisea
Synlett, 2003Co-Authors: Rumi Ueda, Takayuki OritaniAbstract:Pyricuol, a novel plant pathogen isolated from rice blast disease fungus Magnaporthe grisea, was synthesized as a racemate from 2,3-dimethylphenol using the [2,3]-Wittig Rearrangement as the key step.
Masahiro Terada - One of the best experts on this subject based on the ideXlab platform.
-
bronsted base catalyzed 2 3 Wittig phospha brook tandem Rearrangement sequence
Organic Letters, 2013Co-Authors: Azusa Kondoh, Masahiro TeradaAbstract:A Bronsted base catalyzed Rearrangement reaction of 2-allyloxy-2-phosphonoacetate derivatives was developed. This reaction proceeded via a [2,3]-Wittig Rearrangement followed by a phospha-Brook Rearrangement. This is the first example of a catalytic [2,3]-Wittig Rearrangement initiated by a Bronsted base.
-
Brønsted Base Catalyzed [2,3]-Wittig/Phospha-Brook Tandem Rearrangement Sequence
2013Co-Authors: Azusa Kondoh, Masahiro TeradaAbstract:A Brønsted base catalyzed Rearrangement reaction of 2-allyloxy-2-phosphonoacetate derivatives was developed. This reaction proceeded via a [2,3]-Wittig Rearrangement followed by a phospha-Brook Rearrangement. This is the first example of a catalytic [2,3]-Wittig Rearrangement initiated by a Brønsted base
