Umpolung of Vinyloxiranes:  Regio- and Stereoselectivity of the In/Pd-Mediated Allylation of Carbonyl Compounds

Pd‐Mediated Reactions of Epoxides

“…The reactions represented by paths d to h in Scheme 13 have already been the subjects of a number of reports and reviews, [78,79] their chemistry being rather similar to that of allylic alcohols, [80] esters, [81] and carbonates.…”

“…[116,117] Under Stille conditions, the reaction between palladium and 3,4-epoxycyclohex-1-en-2-yl trifluoromethanesulfonate proceeded either at the level of the C-OTf bond or at that of both C-OTf bond and vinyl epoxide moiety [Equation (79)]. [118] In contrast, treatment of the α-epoxy vinyl triflate shown in Equation (80) with a stoichiometric amount of palladium afforded an allenic alcohol through the selective insertion of Pd 0 into the C-OTf bond, leading to 26A (Scheme 26).…”

Synthesis of Furanosyl C‐1 Glycals through Palladium‐Catalyzed Reactions of a Furanosyl 2,3‐Anhydro‐exo‐glycal

“…These included treatment with chromium, [46] tin, [47] samarium, [48] and indium. [49] More recently, Et 3 B and Et 2 Zn have also been used in the Pd-catalyzed generation of nucleophilic allyl species from allyl esters and ethers. [50] In this context, we decided to study the umpolung of the π-allylpalladium species 7 with SmI 2 and Et 2 Zn.…”

A novel entry to C-glycals via diethylzinc-mediated umpolung of π-allyl palladium derived from 1-exo-methylene 2,3-anhydrofuranoses

“…However, one related example involving umpolung of simple vinyloxiranes by indium/palladium-mediated allylation of carbonyl compounds has been described. 14 More recently, on an interesting approach to carbocycles from carbohydrates, Aurrecoechea and co-workers have disclosed the use of Et 2 Zn/Pd(0) for the in situ generation of nucleophilic allylzinc species, which reacted with a ring-opened carbohydrate aldehyde. 15 We have tested aldehydes, ketones and pyranosidic hemiacetals as electrophilic partners.…”