Co‐Catalyzed Asymmetric Intramolecular [3+2] Cycloaddition of Yne‐Alkylidenecyclopropanes and its Reaction Mechanism
作者:Xiong Xiao、Zhi‐Xiang Yu
DOI:10.1002/chem.202100426
日期:2021.4.26
new transition metal‐catalyzed asymmetric cycloadditions for the synthesis of five‐membered carbocycles (FMCs) is a research frontier in reaction development due to the ubiquitous presence of chiral FMCs in various functional molecules. Reported here is our discovery of a highly enantioselective intramolecular [3+2] cycloaddition of yne‐alkylidenecyclopropanes (yne‐ACPs) to bicyclo[3.3.0]octadiene and
Rhodium-catalyzed [(3+2)+1] carbocyclizations of alkynylidenecyclopropanes with carbon monoxide: construction of polysubstituted bicyclohexa-2,5-dienones
作者:Andrew J. Burnie、P. Andrew Evans
DOI:10.1039/c8cc02269k
日期:——
described. This protocol offers convenientaccess to doubly conjugated cyclic enones and is tolerant of functionalized alkynes and cyclopropanes. Furthermore, a photochemical rearrangement of a bicyclohexa-2,5-dienone facilitates the construction of a highly functionalized bicyclopentenone containing two contiguous stereogenic centres, which represents a versatileintermediate for target directed synthesis
Stereoselective Rhodium-Catalyzed [3 + 2 + 1] Carbocyclization of Alkenylidenecyclopropanes with Carbon Monoxide: Theoretical Evidence for a Trimethylenemethane Metallacycle Intermediate
作者:Shivnath Mazumder、Deju Shang、Daniela E. Negru、Mu-Hyun Baik、P. Andrew Evans
DOI:10.1021/ja305467x
日期:2012.12.26
The theoretically inspired development of a Rh-catalyzed [3 + 2 + 1] carbocyclization of carbon- and heteroatom-tethered alkenylidenecyclopropanes (ACPs) with CO for the stereoselective construction of cis-fused bicyclohexenones is described. This study demonstrates that the ring opening of alkylidenecyclopropane proceeds through a Rh(III)-trimethylenemethane complex, which undergoes rate-determining
Intramolecular Rhodium-Catalyzed [(3+2+2)] Carbocyclization Reactions with Dienylidenecyclopropanes: A Concise and Stereoselective Total Synthesis of the Sesquiterpene (+)-Zizaene
作者:Yu Zhu、Jie Zheng、P. Andrew Evans
DOI:10.1021/jacs.2c10923
日期:——
for the construction of bridged tricyclic compounds with up to three quaternary centers, which are suitable for the synthesis of challenging bioactive natural products. For instance, the synthetic utility of this transformation is illustrated through a concise asymmetric totalsynthesis of the sesquiterpene (+)-zizaene in ten steps from a commercially available starting material.
A concise and enantioselective approach to cyclobutanones by tandem asymmetric epoxidation and enantiospecific ring expansion of cyclopropylidene alcohols. An enantiocontrolled synthesis of (+)- and (-)-.alpha.-cuparenones
A tandem Katsuki-Sharpless asymmetric epoxidation and enantiospecific ring expansion of 2-alkyl(or 2-aryl)-2-cyclopropylideneethanols (1a-i) afforded chiral 1-alkyl(or 1-aryl)-1-(hydroxymethyl)cyclobutanones (3a-i) in high yields and high enantiomeric excess. These compounds are potentially valuable synthons for the enantioselective creation of the quaternary carbons. Hence, this enabled us to accomplish a concise and enantioselective total synthesis of both (+)- and (-)-alpha-cuparenones (11).