Stereoselective syntheses of terpenoids in a more efficient manner have been a long-term pursuit for synthetic chemists. Herein we describe the two-step, enantiospecific and protecting-group-free synthesis of (+)-schisanwilsonene A from a carotane compound, which was produced in E. coli. We also completed the first enantiomeric synthesis of (+)-tormesol in five steps. The two-stage strategy offers
作者:Li-Hua Li、Xiao-Lin Feng、Xiao-Hui Cui、Yun-Xiang Ma、San-Yuan Ding、Wei Wang
DOI:10.1021/jacs.7b01523
日期:2017.5.3
The Salen unit represents one of the most important ligands in coordination chemistry. We report herein the first example of a Salen-based covalentorganicframework (COF), in which both the construction of the COF structure and the functionalization with Salen moieties have been realized in a single step. Due to its structural uniqueness, the obtained COF material, Salen-COF, possesses high crystallinity
Mechanistic Basis for High Stereoselectivity and Broad Substrate Scope in the (salen)Co(III)-Catalyzed Hydrolytic Kinetic Resolution
作者:David D. Ford、Lars P. C. Nielsen、Stephan J. Zuend、Charles B. Musgrave、Eric N. Jacobsen
DOI:10.1021/ja408027p
日期:2013.10.16
In the (salen)Co(III)-catalyzed hydrolytickineticresolution (HKR) of terminal epoxides, the rate- and stereoselectivity-determining epoxide ring-opening step occurs by a cooperative bimetallic mechanism with one Co(III) complex acting as a Lewis acid and another serving to deliver the hydroxide nucleophile. In this paper, we analyze the basis for the extraordinarily high stereoselectivity and broad
Titanium–salen complexes as initiators for the ring opening polymerisation of rac-lactide
作者:Charlotte K. A. Gregson、Ian J. Blackmore、Vernon C. Gibson、Nicholas J. Long、Edward L. Marshall、Andrew J. P. White
DOI:10.1039/b518266b
日期:——
A family of bis(iso-propoxide) titanium(IV) complexes supported by tetradentate Schiff base (salen) ligands has been synthesised and characterised, including a structural determination of N,Nâ²-bis(6â²-methylenimino-2â²,4â²-di-tert-butylphenoxy)cyclohexyl-(1R,2R)-diamino titanium(IV) bis(iso-propoxide). Their suitability for initiating the ring-opening polymerisation of rac-lactide has been investigated. Polymerisation activities are shown to correlate with the electronic properties of the substituents within the salen ligand. In contrast to aluminiumâsalen initiators, electron-withdrawing substituents on the Schiff base ligand have a detrimental influence upon polymerisation activities, whereas the use of electron-donating alkoxy-functionalised ligands has allowed the highest recorded activity to date for a titanium-based initiator.
Synthesis and Properties of Salen-Aluminum Complexes as a Novel Class of Color-Tunable Luminophores
作者:Kyu Young Hwang、Hyoseok Kim、Yoon Sup Lee、Min Hyung Lee、Youngkyu Do
DOI:10.1002/chem.200900137
日期:2009.6.22
Showing their true colors? Full emission color tuning in the visible region can be achieved with salen–aluminumcomplexes that are electronically modulated at C5 of the phenoxide ring in the salen moiety. Emission spectra for various substituents R5 are shown (EWG: electron‐withdrawing group, EDG: electron‐donating group).