217446-32-7Relevant academic research and scientific papers
Enantioselective synthesis of pyrano[2,3-: C] pyrrole via an organocatalytic [4 + 2] cyclization reaction of dioxopyrrolidines and azlactones
Wang, Yichen,Chen, Yuzhen,Li, Xiaoping,Mao, Yukang,Chen, Weiwen,Zhan, Ruoting,Huang, Huicai
supporting information, p. 3945 - 3950 (2019/04/30)
An enantioselective [4 + 2] cyclization reaction of dioxopyrrolidines and azlactones has been successfully developed through a squaramide catalysis strategy. This protocol provides an efficient and mild access to obtain pyrano[2,3-c]pyrrole scaffolds containing contiguous quaternary and tertiary stereogenic centers in excellent yields (up to 99%) with high levels of diastereo- and enantioselectivities (up to 99% ee). Two possible pathways were proposed to explain the observed stereoselectivity.
Regiodivergent Enantioselective γ-Additions of Oxazolones to 2,3-Butadienoates Catalyzed by Phosphines: Synthesis of α,α-Disubstituted α-Amino Acids and N,O-Acetal Derivatives
Wang, Tianli,Yu, Zhaoyuan,Hoon, Ding Long,Phee, Claire Yan,Lan, Yu,Lu, Yixin
supporting information, p. 265 - 271 (2016/01/25)
Phosphine-catalyzed regiodivergent enantioselective C-2- and C-4-selective γ-additions of oxazolones to 2,3-butadienoates have been developed. The C-4-selective γ-addition of oxazolones occurred in a highly enantioselective manner when 2-aryl-4-alkyloxazol-5-(4H)-ones were employed as pronucleophiles. With the employment of 2-alkyl-4-aryloxazol-5-(4H)-ones as the donor, C-2-selective γ-addition of oxazolones took place in a highly enantioselective manner. The C-4-selective adducts provided rapid access to optically enriched α,α-disubstituted α-amino acid derivatives, and the C-2-selective products led to facile synthesis of chiral N,O-acetals and γ-lactols. Theoretical studies via DFT calculations suggested that the origin of the observed regioselectivity was due to the distortion energy that resulted from the interaction between the nucleophilic oxazolide and the electrophilic phosphonium intermediate.
Isothiourea-catalyzed enantioselective carboxy group transfer
Joannesse, Caroline,Johnston, Craig P.,Concellon, Carmen,Simal, Carmen,Philp, Douglas,Smith, Andrew D.
supporting information; experimental part, p. 8914 - 8918 (2010/02/28)
Transferable skills: Enantiomerically pure isothioureas promote the 0-to C-carboxyl group transfer of oxazolyl carbonates with excellent levels of enantiocontrol (see scheme). The origin of the enantioselectivity of this process was probed mechanistically and rationalized computationally.
