- Using the competing enantioselective conversion method to assign the absolute configuration of cyclic amines with BODE’s acylation reagents
-
The competing enantioselective conversion (CEC) method is a quick and reliable means to determine absolute configuration. Previously, Bode’s chiral acylated hydroxamic acids were used to determine the stereochemistry of primary amines, as well as cyclic and acyclic secondary amines. The enantioselective acylation has been evaluated for 4-, 5-, and 6-membered cyclic secondary amines, including medicinally relevant compounds. The limitations of the method were studied through computational analysis and experimental results. Piperidines with substituents at the 2-position did not behave well unless the axial conformer was energetically accessible, which is consistent with the transition state geometries proposed by Bode and Kozlowski. Control experiments were performed to investigate the cause of degrading selectivity under the CEC reaction conditions. The present study expands the scope of the CEC method for secondary amines and provides a better understanding of the reaction profile.
- Dooley, Charles J.,Burtea, Alexander,Mitilian, Christina,Dao, Wendy T.,Qu, Bo,Salzameda, Nicholas T.,Rychnovsky, Scott D.
-
p. 10750 - 10759
(2020/10/02)
-
- Catalytic Asymmetric Synthesis of Morpholines. Using Mechanistic Insights to Realize the Enantioselective Synthesis of Piperazines
-
An efficient and practical catalytic approach for the enantioselective synthesis of 3-substituted morpholines through a tandem sequential one-pot reaction employing both hydroamination and asymmetric transfer hydrogenation reactions is described. Starting from ether-containing aminoalkyne substrates, a commercially available bis(amidate)bis(amido)Ti catalyst is utilized to yield a cyclic imine that is subsequently reduced using the Noyori-Ikariya catalyst, RuCl [(S,S)-Ts-DPEN] (η6-p-cymene), to afford chiral 3-substituted morpholines in good yield and enantiomeric excesses of >95%. A wide range of functional groups is tolerated. Substrate scope investigations suggest that hydrogen-bonding interactions between the oxygen in the backbone of the ether-containing substrate and the [(S,S)-Ts-DPEN] ligand of the Ru catalyst are crucial for obtaining high ee's. This insight led to a mechanistic proposal that predicts the observed absolute stereochemistry. Most importantly, this mechanistic insight allowed for the extension of this strategy to include N as an alternative hydrogen bond acceptor that could be incorporated into the substrate. Thus, the catalytic, enantioselective synthesis of 3-substituted piperazines is also demonstrated.
- Lau, Ying Yin,Zhai, Huimin,Schafer, Laurel L.
-
p. 8696 - 8709
(2016/10/14)
-
- Stereoelectronic basis for the kinetic resolution of n-heterocycles with chiral acylating reagents
-
The kinetic resolution of N-heterocycles with chiral acylating agents reveals a previously unrecognized stereoelectronic effect in amine acylation. Combined with a new achiral hydroxamate, this effect makes possible the resolution of various N-heterocycles by using easily prepared reagents. A transition-state model to rationalize the stereochemical outcome of this kinetic resolution is also proposed.
- Hsieh, Sheng-Ying,Wanner, Benedikt,Wheeler, Philip,Beauchemin, Andre M.,Rovis, Tomislav,Bode, Jeffrey W.
-
supporting information
p. 7228 - 7231
(2014/06/23)
-
- KINETIC RESOLUTION OF CHIRAL AMINES
-
The present invention refers to a method for the kinetic resolution of a chiral primary or secondary amine by treating the amine with a chiral, hydroxamic acid derived reagent of the formula (I). These chiral reagents are particularly useful for the kinetic resolution of cyclic amines and may be generated in situ in the presence of an N-heterocyclic carbene, thus allowing for a catalytic reaction.
- -
-
Page/Page column 127
(2013/03/26)
-
- Catalytic asymmetric synthesis of substituted morpholines and piperazines
-
Under two conditions: Hydroamination catalyzed by group 4 metals is featured in the modular and enantioselective synthesis of 3-substituted morpholines and the diastereoselective synthesis of 2,5-substituted piperazines. Copyright
- Zhai, Huimin,Borzenko, Andrey,Lau, Ying Yin,Ahn, Shin Hye,Schafer, Laurel L.
-
supporting information
p. 12219 - 12223
(2013/02/23)
-
- Expanded substrate scope and catalyst optimization for the catalytic kinetic resolution of N-heterocycles
-
The scope, reactivity, and selectivity of the chiral hydroxamic acid-catalyzed kinetic resolution of chiral amines are improved by a new catalyst structure and a more environmentally friendly reaction protocol. In addition to increasing selectivity across all substrates, these conditions make possible the resolution of N-heterocycles containing lactams or other basic functional groups that can inhibit the catalyst.
- Hsieh, Sheng-Ying,Binanzer, Michael,Kreituss, Imants,Bode, Jeffrey W.
-
supporting information
p. 8892 - 8894
(2012/11/07)
-
- Catalytic kinetic resolution of cyclic secondary amines
-
The catalytic resolution of racemic cyclic amines has been achieved by an enantioselective amidation reaction featuring an achiral N-heterocyclic carbene catalyst and a new chiral hydroxamic acid cocatalyst working in concert. The reactions proceed at room temperature, do not generate nonvolatile byproducts, and provide enantioenriched amines by aqueous extraction.
- Binanzer, Michael,Hsieh, Sheng-Ying,Bode, Jeffrey W.
-
supporting information; experimental part
p. 19698 - 19701
(2012/01/13)
-
- 4-(1,3-Thiazol-2-yl)morpholine derivatives as inhibitors of phosphoinositide 3-kinase
-
4-(1,3-Thiazol-2-yl)morpholine derivatives have been identified as potent and selective inhibitors of phosphoinositide 3-kinase. The SAR data of selected examples are presented and the in vivo profiling of compound 18 is shown to demonstrate the utility of this class of compounds in xenograft models of tumor growth.
- Alexander, Rikki,Balasundaram, Ahrani,Batchelor, Mark,Brookings, Daniel,Crepy, Karen,Crabbe, Tom,Deltent, Marie-France,Driessens, Frank,Gill, Andrew,Harris, Sue,Hutchinson, Gillian,Kulisa, Claire,Merriman, Mark,Mistry, Prakash,Parton, Ted,Turner, James,Whitcombe, Ian,Wright, Sara
-
scheme or table
p. 4316 - 4320
(2009/04/06)
-