Highly stereoselective generation of α-pyrones displaying four contiguous stereogenic centers

Silylated Vinyloxiranes – Recent Advances and Synthetic Applications

“…In our case, the diastereoselectivity of the addition of organometallic derivatives to compound 3a is governed by the silicon atom bound to the lactone at the γ position 28. This reverses the stereochemical fate of this conjugated addition, which now takes place anti to the silyl group and therefore syn to the isopropyl substituent, in the equatorial position on the six‐membered ring, as described in Table 2.…”

Diastereoselective thiol conjugate addition on δ-alkylated-γ-silylated-α,β-unsaturated-δ-lactones

“…In particular, we focused recently on diastereoselective conjugate additions which may be followed by electrophilic trapping. 1 We demonstrated that these two former reactions can be included in a four-step one-pot transformation of α,β-epoxy-γ,δ-vinyl-silanes 2, directly into tetra-substituted δ-lactones 3.…”

“…As we have reported recently, 1 our group is currently involved in investigating the reactivity field of δ-alkylated-γ-silylated-α,β-unsaturated δ-lactones 1. These compounds are easily synthesized in enantiomerically pure forms and in a highly diastereoselective manner by a tandem rearrrangement / alkylation-lactonization sequence starting from α,β-epoxy-γ,δ-vinylsilanes 2.…”

Pd‐Mediated Reactions of Epoxides

“…[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).…”