93361-67-2Relevant academic research and scientific papers
Total Synthesis of Rishirilide B by Organocatalytic Oxidative Kinetic Resolution: Revision of Absolute Configuration of (+)-Rishirilide B
Odagi, Minami,Furukori, Kota,Takayama, Kan,Noguchi, Keiichi,Nagasawa, Kazuo
, p. 6609 - 6612 (2017)
Described herein is the enantioselective syntheses of (+)- and (?)-rishirilide B from the corresponding optically active β-substituted tetralones, which were obtained by oxidative kinetic resolution based on α-hydroxylation in the presence of a chiral guanidine-bisurea bifunctional organocatalyst. Benzylic oxidation of the tetralones at C1 followed by regioselective isomerization of the oxabenzonorbornadiene structure led to rishirilide B. Our findings lead to the revision of the previously proposed (2R,3R,4R) absolute configuration of (+)-rishirilide B to (2S,3S,4S).
Oxidative Carbon Backbone Rearrangement in Rishirilide Biosynthesis
Bechthold, Andreas,Frensch, Britta,Makitrynskyy, Roman,Paululat, Thomas,Teufel, Robin,Tsypik, Olga,Zechel, David L.
supporting information, p. 5913 - 5917 (2020/04/27)
The structural diversity of type II polyketides is largely generated by tailoring enzymes. In rishirilide biosynthesis by Streptomyces bottropensis, 13C-labeling studies previously implied extraordinary carbon backbone and side-chain rearrangements. In this work, we employ gene deletion experiments and in vitro enzyme studies to identify key biosynthetic intermediates and expose intricate redox tailoring steps for the formation of rishirilides A, B, and D and lupinacidin A. First, the flavin-dependent RslO5 reductively ring-opens the epoxide moiety of an advanced polycyclic intermediate to form an alcohol. Flavin monooxygenase RslO9 then oxidatively rearranges the carbon backbone, presumably via lactone-forming Baeyer-Villiger oxidation and subsequent intramolecular aldol condensation. While RslO9 can further convert the rearranged intermediate to rishirilide D and lupinacidin A, an additional ketoreductase RslO8 is required for formation of the main products rishirilide A and rishirilide B. This work provides insight into the structural diversification of aromatic polyketide natural products via unusual redox tailoring reactions that appear to defy biosynthetic logic.
Total synthesis of (+)-rishirilide B: Development and application of general processes for enantioselective oxidative dearomatization of resorcinol derivatives
Mejorado, Lupe H.,Pettus, Thomas R. R.
, p. 15625 - 15631 (2007/10/03)
A concise synthesis of (+)-rishirilide B (2) is described. This is the first synthesis to be reported for the (+)-enantiomer of rishirilide B (2) as found in nature. The strategy accentuates the valuable combination of a method for oquinone methide coupli
On the total synthesis and determination of the absolute configuration of rishirilide B: Exploitation of subtle effects to control the sense of cycloaddition of o-quinodimethides
Yamamoto, Kana,Hentemann, Martin F.,Allen, John G.,Danishefsky, Samuel J.
, p. 3242 - 3252 (2007/10/03)
The total synthesis of racemic rishirilide B has been accomplished. The synthesis serves to define the relative relationships of its stereogenic centers. Also, starting with readily available chiral pool, ent-rishirilide B was synthesized, thereby demonst
