899429-24-4Relevant academic research and scientific papers
Proline Ester Enolate Claisen Rearrangement and Formal Total Synthesis of (-)-Cephalotaxine
Jeon, Hongjun,Chung, Yundong,Kim, Sanghee
, p. 8080 - 8089 (2019)
A concise formal total synthesis of (-)-cephalotaxine was achieved via an ester enolate Claisen rearrangement (EECR). A series of EECRs of proline allyl esters were examined to obtain the desired relative stereochemistry of an azaspiranic tetracyclic backbone. An unexpected reversal or low diastereoselectivity of (Z)-cinnamyl ester was observed. The diastereoselectivity was controlled by substitution patterns of a styrene region. This result represents a useful guide in aiding the prediction of stereochemical outcome of EECR of α-amino allylic esters.
N-Alkylation of α-Amino Esters and Amides through Hydrogen Borrowing
Coomber, Charlotte E.,Diorazio, Louis J.
supporting information, (2022/03/31)
The iridium catalysed N-alkylation of α-amino esters and amides using alcohols through hydrogen borrowing has been developed. The protocol can be applied to both the free base and hydrochloride salts of the amines and produces water as the only by-product. This transformation can provide easy access to chiral N-alkyl amines from readily available starting materials in a simple one step reaction.
Asymmetric [1,2] Stevens rearrangement of (S)-N-benzylic proline-derived ammonium salts under biphasic conditions
Tayama, Eiji,Nanbara, Shintaro,Nakai, Takeshi
, p. 478 - 479 (2007/10/03)
The Stevens rearrangement of (S)-N-benzylic proline-derived ammonium salt with cesium hydroxide in 1,2-dichloroethane is shown to proceed with a high degree of the N-to-C chirality transmission to afford the α-substituted proline derivatives in high enantio-purities. Copyright
