A Convergent Hetero‐Diels–Alder Strategy for Asymmetric Access to a Lactone Containing Two Lipidic Chains

Abstract

International audienc

Photoinduced Multicomponent Synthesis of α-Silyloxy Acrylamides, an Unexplored Class of Silyl Enol Ethers

“…For this reason, reactions with aldehydes under Mukayama conditions failed to afford the desired products, and employment of organocatalysis afforded the aldol products in unsatisfactory yields. Nevertheless, generation of the enolate in situ with addition of TBAF was successful: Mannich reaction of 1a with Eschenmoser’s salt gave the desired elimination product 7 in 83% yield (Scheme ); α,β-unsaturated ketoesters have been efficiently employed in asymmetrical conjugate additions and cycloadditions; therefore, our method offers new substrates to assemble isoxazolines, carbazoles, dihydropyrans, or cyclic nitrones with an additional amide functional group.…”

2,8-Diheterobicyclo[3.2.1]octane Ring Systems: Natural Occurrence, Synthesis and Properties

“…The process involves the reductive ring-expansion of bicyclic compounds containing an α-nitroketone function with the nitro group in a bridgehead position, coupled with a Nef reaction, and the final intramolecular formation of two acetal bonds to complete, in situ, the highly efficient construction of a bridged 2, Meanwhile, Saluzzo and co-workers observed these systems during their work on the synthesis of ceramide analogues. 34 Thus, removal of the 1,3-oxazolidin-2-one chiral auxiliary fragment in compound 3 led to bicyclic compound 4 in 35% yield, along with unreacted starting material (Scheme 11). In the area of gold-catalyzed organic reactions, the cyclizations of alkynyl ketones/aldehydes have emerged as a powerful strategy for the construction of various cyclic ring systems.…”

“…Meanwhile, Saluzzo and co-workers observed these systems during their work on the synthesis of ceramide analogues. 34 Thus, removal of the 1,3-oxazolidin-2-one chiral auxiliary fragment in compound 3 led to bicyclic compound 4 in 35% yield, along with unreacted starting material (Scheme 11). In the area of gold-catalyzed organic reactions, the cyclizations of alkynyl ketones/aldehydes have emerged as a powerful strategy for the construction of various cyclic ring systems.…”

Metal Promoted Diels-Alder Reactions

“…Although very mild Lewis acid, they have shown that this catalyst can be used under hyperbaric conditions when the intrinsic reactivity of the partners is too low [135]. The reaction between , -unsaturated--ketoester 239 and chiral N-alkenyloxazolidinones 240 is highly endo selective (Scheme 72) when catalysed by Eu(fod) 3 (assuming a concerted mechanism occurs) whereas a complete reversed facial selectivity is observed when SnCl 4 is used (explained by the formation of a zwitterionic intermediate) [136]. In addition, the yields are lower due to the high acidic character of SnCl 4 (partial decomposition of the heterodiene).…”