Foldamer-mediated remote stereocontrol: >1,60 asymmetric induction.
نویسندگان
چکیده
An N-terminal L-α-methylvaline dimer induces complete conformational control over the screw sense of an otherwise achiral helical peptide foldamer formed from the achiral quaternary amino acids Aib and Ac6 c. The persistent right-handed screw-sense preference of the helix enables remote reactive sites to fall under the influence of the terminal chiral residues, and permits diastereoselective reactions such as alkene hydrogenation or iminium ion addition to take place with 1,16-, 1,31-, 1,46- and even 1,61-asymmetric induction. Stereochemical information may be communicated in this way over distances of up to 4 nm.
منابع مشابه
Enantioselective total synthesis of callipeltoside A.
An asymmetric total synthesis of callipeltoside A has been accomplished highlighted by a catalytic enantioselective vinylogous aldol reaction and a boron-mediated anti-aldol reaction influenced by remote stereocontrol.
متن کاملRefoldable Foldamers: Global Conformational Switching by Deletion or Insertion of a Single Hydrogen Bond.
Small changes in the structure of a foldamer may lead to gross changes in conformational preference. We show that the simple insertion or deletion of a single hydrogen bond by changes in pH or by photochemical deprotection is sufficient to refold a helical oligomer, interconverting M and P screw-sense preference. As a consequence of the switch, information may be transmitted to a remote catalyt...
متن کاملRemote functionalization of hydrocarbons with reversibility enhanced stereocontrol.
Remote functionalization of hydrocarbons could be achieved through successive zirconocene-mediated allylic C-H bond activations followed by a selective C-C bond cleavage. Determination of the reaction mechanism by density functional theory (DFT) calculations shows that the high stereocontrol observed in this process results from a large number of energetically accessible equilibria feeding a pr...
متن کاملCopper-catalyzed asymmetric allylation of chiral N-tert-butanesulfinyl imines: dual stereocontrol with nearly perfect diastereoselectivity.
Copper-catalyzed asymmetric allylation of chiral N-tert-butanesulfinyl imines has been described. Dual stereocontrol, through the combination of a chiral auxiliary and a chiral copper complex, has played an important role in achieving the nearly perfect diastereoselectivities (all dr > 99 : 1), especially for ketimine substrates.
متن کاملSmI2-mediated radical cyclizations directed by a C-Si bond.
The use of a silicon stereocontrol element in cyclobutanol and cyclopentanol-forming cyclizations mediated by SmI(2) results in excellent diastereocontrol. The C-Si bond in the products of cyclization provides a versatile handle for further manipulation. An asymmetric route to cyclization substrates involving copper-catalyzed silyl transfer has also been developed.
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Angewandte Chemie
دوره 53 1 شماره
صفحات -
تاریخ انتشار 2014