- Asymmetric Transfer Hydrogenation: Dynamic Kinetic Resolution of α-Amino Ketones
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A series of α-amino ketones were reduced using asymmetric transfer hydrogenation (ATH) through a dynamic kinetic resolution (DKR). The protecting group was matched to the reducing agent, and following optimization, a series of substrates were investigated, giving products in high diastereoselectivity, over 99% ee in several cases and full conversion. The methodology was applied to the enantioselective synthesis of an MDM2-p53 inhibitor precursor.
- Gediya, Shweta K.,Clarkson, Guy J.,Wills, Martin
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- Synthesis of Aminomethylene- gem-bisphosphonates Containing an Aziridine Motif: Studies of the Reaction Scope and Insight into the Mechanism
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A broad range of N-carbamoylaziridines were obtained and then treated by the diethyl phosphonate anion to afford α-methylene-gem-bisphosphonate aziridines. Study of the reaction's scope and additional experiments indicates that the transformation proceeds via a new mechanism involving the chelation of lithium ion. This last step is crucial for the reaction to occur and disfavors the aziridine ring-opening. A phosphonate-phosphate rearrangement from a α-hydroxybisphosphonate aziridine intermediate is also proposed for the first time. This reaction provides a simple and convenient method for the synthesis of a highly functionalized phosphonylated aziridine motif.
- Cheviet, Thomas,Peyrottes, Suzanne
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p. 3107 - 3119
(2021/02/05)
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- The Preparation of (1α,3β)-3-Hydroxycholestane-4,6-diene- 1,25-diol Diacetate from a 5,7-Diene Precursor: A New Method for the Synthesis of Heteroannular Dienes
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Starting from the 7α-bromide 5a, a regioselective synthesis of (1α,3β)-3-hydroxycholestane-4,6-diene-1,25-diol diacetate (2) is described. The preparative removal of contaminating 5,7-diene 9 was accomplished by the formation of the corresponding Diels-Alder adduct 11. Acetylation of the diacetate 2 followed by acid-catalyzed elimination and rearrangement yielded styrene 13.
- Arnum, Susan D. Van,Carpenter, Barry K.,Parrish, David R.,MacIntrye, Archibald
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p. 8533 - 8536
(2007/10/03)
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