CF3 on C: Trifluoromethylation of allylsilane derivatives was accomplished through the use of CuI and Togni's reagent (1) under mild conditions. The reaction of allylsilanes without a substituent in the 2‐position gave vinylsilane derivatives, while 2‐substituted allylsilanes afforded desilylated products. The utility of the products was demonstrated through their further transformation.
Enantioselective Synthesis of α-Allyl Amino Esters via Hydrogen-Bond-Donor Catalysis
作者:Andrew J. Bendelsmith、Seohyun Chris Kim、Masayuki Wasa、Stéphane P. Roche、Eric N. Jacobsen
DOI:10.1021/jacs.9b05556
日期:2019.7.24
diastereoselec-tive synthesis of α-allyl amino esters. The optimized protocol provides access to N-carbamoyl-protected amino esters via nucleophilic allyla-tion of readily accessible α-chloro glycinates. A variety of useful α-allyl amino esters were prepared-including crotylated products bearing vicinal stereocenters that are inaccessible through enolate alkylation-with high enantioselectivity (up to 97% ee)
Palladium-Catalyzed Cross-Coupling Reaction of Bis(pinacolato)diboron with 1-Alkenyl Halides or Triflates: Convenient Synthesis of Unsymmetrical 1,3-Dienes via the Borylation-Coupling Sequence
1-alkenylboronic acid pinacol esters via a palladium-catalyzed cross-coupling reaction of bis(pinacolato)diboron (pin(2)B(2), pin = Me(4)C(2)O(2)) with 1-alkenyl halides or triflates was carried out in toluene at 50 degrees C in the presence of KOPh (1.5 equiv) and PdCl(2)(PPh(3))(2)-2Ph(3)P (3 mol %). The borylation of acyclic and cyclic 1-alkenyl bromides and triflates was achieved in high yields with complete
Radical alkylations of activated alkyl iodides and bromides were achieved usingvinyltriflates in the presence of hexadimethyltin, whereas those of unactivated C-H bonds usingvinyltriflates proceeded cleanly under tin-free conditions.
Radical Desulfur‐Fragmentation and Reconstruction of Enol Triflates: Facile Access to α‐Trifluoromethyl Ketones
作者:Xiaolong Su、Honggui Huang、Yaofeng Yuan、Yi Li
DOI:10.1002/anie.201608507
日期:2017.1.24
efficient oxidative radical desulfur‐fragmentation and reconstruction of enoltriflates for the synthesis of α‐CF3 ketones. Preliminary mechanistic studies disclosed that oxidative fragmentation to release a CF3 radical from the triflyl group of enoltriflate and subsequent addition of the CF3 radical to another enoltriflate form the desired α‐CF3 ketones. This method provides a new approach to α‐CF3