129042-95-1Relevant articles and documents
Enantioselective Synthesis of Pyroglutamic Acid Esters from Glycinate via Carbonyl Catalysis
Ma, Jiguo,Zhou, Qinghai,Song, Guanshui,Song, Yongchang,Zhao, Guoqing,Ding, Kuiling,Zhao, Baoguo
supporting information, p. 10588 - 10592 (2021/04/06)
Direct α-functionalization of NH2-free glycinates with relatively weak electrophiles such as α,β-unsaturated esters still remains a big challenge in organic synthesis. With chiral pyridoxal 5 d as a carbonyl catalyst, direct asymmetric conjugated addition at the α-C of glycinate 1 a with α,β-unsaturated esters 2 has been successfully realized, to produce various chiral pyroglutamic acid esters 4 in 14–96 % yields with 81–97 % ee's after in situ lactamization. The trans and cis diastereomers can be obtained at the same time by chromatography and both of them can be easily converted into chiral 4-substituted pyrrolidin-2-ones such as Alzheimer's drug Rolipram (11) with the same absolute configuration via tert-butyl group removal and subsequent Barton decarboxylation.
Cascade reaction including a formal [5?+?2] cycloaddition by use of alkyne-Co2(CO)6 complex
Sakata, Yuki,Yasui, Eiko,Mizukami, Megumi,Nagumo, Shinji
supporting information, p. 755 - 759 (2019/02/20)
A new cascade reaction including formal [5 + 2] cycloaddition was developed. Treatment of homocinnamyl alcohol and Co2(CO)6-complexed arylpropynal with BF3·OEt2 resulted in the generation of hydrobenzocyclohepta
Total synthesis of bryostatin 2
Evans, David A.,Carter, Percy H.,Carreira, Erick M.,Charette, André B.,Prunet, Jo?lle A.,Lautens, Mark
, p. 7540 - 7552 (2007/10/03)
The total synthesis of the marine macrolide bryostatin 2 is described. The synthesis plan relies on aldol and directed reduction steps in order to construct the anti-1,3-diol array present in each of the principal subunits (A, B, and C). These fragments were coupled using a Julia olefination and subsequent sulfone alkylation. A series of functionalization reactions provided a bryopyran seco acid, which was macrolactonized under Yamaguchi conditions. Installation of the two enoate moieties took advantage of asymmetric phosphonate and aldol condensation strategies. Reduction of the C20 ketone and simple protecting group operations then completed the synthesis of bryostatin 2. This flexible approach should provide access to a series of new analogues of this clinically important marine natural product.
