- Rhodium-catalyzed hydrocarbonylation of a homoallylamine via n-h activation and application for synthesis of yohimbane alkaloids
-
We describe syntheses of n-yohimbane and alloyohimbane using Rh-catalyzed hydrocarbonylation, which provides a practical methodology to synthesize a δ-lactam from a secondary homoallyl amine. We have also observed an unexpected transformation where the am
- Chiou, Wen-Hua,Wang, Yu-Wei,Kao, Chien-Lun,Chen, Po-Chou,Wu, Chen-Chang
-
-
Read Online
- A Concise, Enantioselective Approach for the Synthesis of Yohimbine Alkaloids
-
We report a concise, enantioselective synthesis of the yohimbine alkaloids (-)-rauwolscine and (-)-alloyohimbane. The key transformation involves a highly enantio- and diastereoselective NHC-catalyzed dimerization and an amidation/N-acyliminium ion cyclization sequence to furnish four of the five requisite rings and three of the five stereocenters in two operations. This route also provides efficient access to all four diastereomeric arrangements of the core stereotriad of the yohimbine alkaloids from a common intermediate. This platform approach in combination with the ability to access both enantiomers from the carbene-catalyzed reaction is a powerful strategy that can produce a wide range of complex alkaloids and related structures for future biomedical investigations.
- Miller, Eric R.,Hovey, M. Todd,Scheidt, Karl A.
-
p. 2187 - 2192
(2020/02/04)
-
- Enantioselective Syntheses of (–)-Alloyohimbane and (–)-Yohimbane by an Efficient Enzymatic Desymmetrization Process
-
Enantioselective syntheses of (–)-alloyohimbane and (–)-yohimbane were accomplished in a convergent manner. The key step involves a modified mild protocol for the enantioselective enzymatic desymmetrization of a meso-diacetate. This provides convenient access to an optically active monoacetate in multi-gram quantities and in high enantiomeric purity. This monoacetate was converted to (–)-alloyohimbane. Reductive amination of the derived aldehyde caused isomerization to the trans-product and, ultimately, the formation of (–)-yohimbane.
- Ghosh, Arun K.,Sarkar, Anindya
-
p. 6001 - 6009
(2016/12/26)
-
- Application of oxidative desymmetrization of meso-tetrahydrofurans: Syntheses of functionalized chiral building blocks and of (-)-alloyohimbane
-
Oxidative desymmetrization of oxygen functionalized mesotetrahydrofurans was successfully achieved (up to 87% ee) through (salen)manganese(III) catalyzed enantiotopic selective C-H oxidation. The enantioselective synthesis of (-)-alloyohimbane (12) has also been achieved in a short step by using oxidative desymmetrization of meso-tetrahydrofuran as the key step.
- Miyafuji, Akio,Ito, Katsuji,Katsuki, Tsutomu
-
p. 261 - 272
(2007/10/03)
-
- Stereoselective Additions of Chiral α-Sulfinyl Ketimine Anions to Ene Esters. Asymmetric Syntheses of Indoloquinolizidine and Yohimban Alkaloids
-
The in-situ 1,4-addition/ring-closure reactions of chiral α-sulfinyl ketimine anions with acyclic and cyclic ene esters offer a simple, convenient route for the construction of chiral cyclic alkaloids having a nitrogen-atom ring juncture.Asymmetric induction in the conjugate-addition reaction of the carbanions derived from α-sulfinyl ketimines possessing chiral sulfur with various cyclic and acyclic ene esters, subsequent ring-closure reaction, and reduction of the resulting β-sulfinyl enamides were utilized in the syntheses of (-)-1,2,3,4,6,7,12,12b-octahydroindoloquinolizine , (-)-alloyohimban , (+)-3-epi-alloyohimban , and (-)-yohimban .
- Hua, Duy H.,Bharathi, S. Narasimha,Panangadan, Jagath A. K.,Tsujimoto, Atsuko
-
p. 6998 - 7007
(2007/10/02)
-
- Stereoselective Addition Reactions of Chiral α-Sulfinyl Ketimine Anions with Ene Esters. Facile Asymmetric Syntheses of Indoloquinolizidine and Yohimbanoid Alkaloids
-
A convenient route for the construction of chiral indolizidines and yohimbanoid alkaloids from the 1,4-addition/ring-closure reactions of α-sulfinyl ketimine anions with ene esters is presented.
- Hua, Duy H.,Bharathi, S. Narasimha,Takusagawa, Fusao,Tsujimoto, Atsuko,Panangadan, Jagath A. K.,et al.
-
p. 5659 - 5662
(2007/10/02)
-
- AN ENANTIOSELECTIVE SYNTHESIS of (-)-ALLOYOHIMBANE
-
A conceptually novel total synthesis of (-)-alloyohimbane is reported.The key step utilizes a groupselective nitrogen insertion process on a meso bicyclic ketone.
- Aube, Jeffrey
-
p. 4509 - 4512
(2007/10/02)
-
- NEW STRATEGY FOR CHIRAL ALKALOID SYNTHESIS COMMENCING WITH A CARBOHYDRATE. SIMPLE SYNTHESIS OF (-)-ALLO-YOHIMBANE FROM LEVOGLUCOSENONE
-
An optically active allo-yohimbane was synthesized in 12 steps from levoglucosenone.The key steps are Diels-Alder cycloaddition for the E-ring construction followed by eliminative Wolff-Kishner reduction and selective double cyclization in the D- and C-ri
- Isobe, Minoru,Fukami, Naoki,Goto, Toshio
-
-