- Dual Activation of Unsaturated Amides with Schwartz's Reagent: A Diastereoselective Access to Cyclopentanols and N,O-Dimethylcyclopentylhydroxylamines.
-
The diastereoselective access to cyclopentanols and N,O-dimethylcyclopentylhydroxylamines from 4-pentenoic acid-derived Weinreb amides is described. Based on the concomitant generation of both the nucleophilic and the electrophilic poles by hydrozirconati
- Coelho, Aurélien,Souvenir Zafindrajaona, Mahasoa-Salina,Vallée, Alexis,Behr, Jean-Bernard,Vasse, Jean-Luc
-
supporting information
(2021/12/06)
-
- Convergent Evolution of Diastereomeric Mixtures of 5-Methoxy-pentylzirconocenes toward Trans-1,2-substituted Cyclopentanes
-
The access to 1,2- and 1,1,2-substituted trans cyclopentanes via a sequential hydrozirconation/TMSOTf-mediated cyclization applied to 5-methoxypent-1-enes is presented. Involving a transient carbocation, the reaction was shown to be diastereo-convergent. Possibly performed in a nonracemic version, the reaction proved compatible with a range of functional groups affording a large panel of cyclopentanes.
- Coelho, Aurélien,Machado-Rodrigues, Carine,Behr, Jean-Bernard,Vasse, Jean-Luc
-
supporting information
p. 772 - 776
(2021/02/01)
-
- Soluble polymer supported 2-imidazolidinone chiral auxiliary and method for manufacturing the same
-
The present invention relates to a chiral auxiliary agent and a manufacturing method thereof and, more specifically, to a 2-imidazolidinone chiral auxiliary agent supported onto a polymer soluble in an organic solvent and a manufacturing method thereof. The chiral auxiliary agent in the present invention shows effects of being easy to separate reaction products and the chiral auxiliary agent after a termination of a reaction while fulfilling an economic efficacy of chiral auxiliary molecules by being supported onto the polymer soluble in the organic solvent.COPYRIGHT KIPO 2015
- -
-
Paragraph 0092; 0097-0101
(2017/01/02)
-
- Solid phase asymmetric alkylation reactions using 2-imidazolidinone chiral auxiliary
-
A novel solid supported 2-imidazolidinone chiral auxiliary was prepared from O-benzyl-l-tyrosine and Wang resin. Asymmetric alkylation reactions in the solid phase proceeded with excellent stereoselectivities, which were even higher than those observed in the conventional solution phase method.
- Nguyen, Quynh Pham Bao,Kim, Jae Nyoung,Kim, Taek Hyeon
-
scheme or table
p. 4015 - 4018
(2009/11/30)
-
- Fluorine-directed diastereoselective iodocyclizations
-
(Chemical Equation Presented) An inside job: β-Fluorinated lactones and tetrahydrofurans are synthesized by iodocyclization of various allylic fluorides. The fluorine substituent acts as a highly efficient syn-stereodirecting group for the ring closure. T
- Tredwell, Matthew,Luft, Jennifer A. R.,Schuler, Marie,Tenza, Kenny,Houk, Kendall N.,Gouverneur, Veronique
-
p. 357 - 360
(2008/09/19)
-
- Remarkable electronic and steric effects in the nitrile biotransformations for the preparation of enantiopure functionalized carboxylic acids and amides: Implication for an unsaturated carbon-carbon bond binding domain of the amidase
-
(Chemical Equation Presented) Biotransformations of various functionalized racemic nitriles catalyzed by Rhodococcus erythropolis AJ270, a nitrile hydratase/amidase-containing microbial whole-cell catalyst, were studied. While the nitrile hydratase exhibi
- Gao, Ming,Wang, De-Xian,Zheng, Qi-Yu,Huang, Zhi-Tang,Wang, Mei-Xiang
-
p. 6060 - 6066
(2008/02/10)
-
- Design and synthesis of a new polymer-supported Evans-type oxazolidinone: An efficient chiral auxiliary in the solid-ph ase asymmetric alkylation reactions
-
Wang resin-supported Evans' chiral auxiliary (23) was designed based on a novel polymer-anchoring strategy, which utilizes the 5-position of the oxazolidinone ring, and its new synthetic route applicable to multi-gram preparation in just a day was developed. Solid-phase Evans' asymmetric alkylation on 23-derived N-acylimide resin and following lithium hydroperoxide-mediated chemoselective hydrolysis afforded the corresponding α-branched carboxylic acids in desired high stereoselectivities (up to 97% ee) and moderate to good overall yield (up to 70%, for 3 steps), which were comparable to those of the conventional solution-phase methods. Furthermore, recovery and recycling of the polymer-supported chiral auxiliary were successfully achieved without decreasing the stereoselectivity of the product. Therefore, this is the first successful example that the solid-phase Evans' asymmetric enolate-alkylation was efficiently performed on the solid-support, and it is concluded that the connection to the solid-support via the 5-position of the oxazolidinone ring is an ideal strategy in the solid-phase Evans' chiral auxiliary.
- Kotake, Tomoya,Hayashi, Yoshio,Rajesh,Mukai, Yoshie,Takiguchi, Yuka,Kimura, Tooru,Kiso, Yoshiaki
-
p. 3819 - 3833
(2007/10/03)
-
- Relationship of stereochemical and skeletal diversity of small molecules to cellular measurement space
-
Systematic and quantitative measurements of the roles of stereochemistry and skeleton-dependent conformational restriction were made using multidimensional screening. We first used diversity-oriented synthesis to synthesize the same number (122) of [10.4.
- Kim, Young-Kwon,Arai, Midori A.,Arai, Takayoshi,Lamenzo, Julia O.,Dean III, Elton F.,Patterson, Nick,Clemons, Paul A.,Schreiber, Stuart L.
-
p. 14740 - 14745
(2007/10/03)
-
- A new polymer-supported Evans-type chiral auxiliary derived from α-hydroxy-β-amino acid, phenylnorstatine: Synthesis and application in solid-phase asymmetric alkylation reactions
-
Based on a new anchoring strategy, a polymer-supported chiral oxazolidinone was prepared starting from (2R,3S)-3-amino-2-hydroxy-4-phenylbutanoic acid (phenylnorstatine, Pns) and Wang resin. Solid-phase asymmetric alkylation on this resin proceeded in high diastereoselectivity comparable to that of conventional solution-phase model experiments. This study suggests that anchoring through the 5-position of oxazolidinone is highly suited to achieving diastereoselective alkylation reactions on solid-support.
- Kotake, Tomoya,Rajesh,Hayashi, Yoshio,Mukai, Yoshie,Ueda, Mitsuhiro,Kimura, Tooru,Kiso, Yoshiaki
-
p. 3651 - 3654
(2007/10/03)
-
- Asymmetric synthesis of intermediates for retroviral protease inhibitor compounds
-
The disclosure describes an improved process for producing optically active compounds of Formula II or III, which compounds are useful as intermediates for preparing compounds active as inhibitors of retroviral protease enzymes: STR1 wherein R1
- -
-
-
- Asymmetric Induction in the Claisen Rearrangement of N-Allylketene N,O-Acetals
-
Asymmetric C-C bond formation via the diastereoselective aza-Claisen rearrangement of N-allylketene N,O-acetal 1 is described.Diastereoselection noted for rearrangement 1->2 ranges from 84percent to 96percent and is a consequence of complete (Z)-N,O-acetal olefin selectivity in 1, high Cα-si-face selectivity in the rearrangement of 1 to 2, and the absence of Cα epimerization in oxazoline 2.Experiments which establish the steric bulk of the C4 appendage as a particularly important variable are also reported.Acid-catalyzed hydrolysis of rearranged oxazoline 2 completes an efficient, enantioselective synthesis of 2-substituted pent-4-enoic acid 4 and regenerates for recycling the chiral auxiliary reagent 3, initially prepared from inexpensive α-amino acids.
- Kurth, Mark J.,Decker, Owen H. W.,Hope, Hakon,Yanuck, Michael D.
-
p. 443 - 448
(2007/10/02)
-