Palladium catalysed direct allylation of pronucleophiles with allylstannanes
作者:Yoshinori Yamamoto、Naoya Fujiwara
DOI:10.1039/c39950002013
日期:——
The reaction of pronucleophiles 1 with allyltributylstannanes in the presence of catalytic amounts of Pd2(dba)3·CHCl3(4 mol%) and 1,2-bis(diphenylphosphino)ethane (dppe)(10 mol%) at room temperature gives the corresponding allylation products in good to high yields.
The non-symmetric azodicarbonyl compound 7 reacted with R-M/Lewis acid regioselectively at the nitrogen atom attached to the amide group giving 9, whereas it reacted with R-M at the nitrogen atom attached to the ester group producing 8 in high yield.
Silver Oxide as a Novel Catalyst for Carbon–Carbon Bond-forming Reactions in Aqueous Media
作者:Masaharu Ueno、Arata Tanoue、Shu Kobayashi
DOI:10.1246/cl.2010.652
日期:2010.6.5
Silver oxide was found to be an excellent catalyst for allylation reactions of allyltributyltins with aldehydes in aqueous media. Despite the very low solubility of silver oxide in the media, the reactions proceeded smoothly, and the catalyst was recovered and reused. When α-methyl-substituted allyltributyltin was used as the nucleophile, the corresponding α-adducts were obtained exclusively in high yields with good anti-selectivity. A reaction mechanism including transmetalation from tin to silver is proposed.
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)
(+)-Migrastatin, an antimetastatic agent, was synthesized by using three ruthenium-catalyzed metathesis reactions: a ring-closing metathesis (RCM) to control the (Z)-trisubstituted double bond at C11–C12, another RCM at C6–C7 to establish the macrolactone core, and a cross-metathesis to install the glutarimide side chain at C16–C17. The stereogenic centers at C9, C10, C13, and C14 were introduced by