Synthesis of the Tricyclic Core of Solanoeclepin A through Intramolecular [2+2] Photocycloaddition of an Allene Butenolide

Abstract

Studies are reported towards the synthesis of solanoeclepin A (1), the hatching agent of potato cyst nematodes. Two approaches are investigated to access the tricyclic core including the intricate bicyclo[2.1.1]hexanone moiety. The first approach is based on the intramolecular [2+2] photocycloaddition of dioxenone butenolide 10 and is shown to be less practical due to the limited synthetic utility of the photoproduct 11. The second approach uses as the key step the intramolecular [2+2] photocycloaddition reaction of allene butenolide 39. This latter photosubstrate is prepared through silver-mediated coupling of silyloxyfuran 9 and allenic bromide

Formation of a Four‐Membered Ring: From a Carbonyl‐Conjugated Alkene

“…The reaction established the intrabridgehead configuration at the stereogenic centers C-8 and C-10 in the target compound (AE)-ingenol (139) [129]. In other recent examples, 1,3-dioxin-4-ones have been employed in synthetic efforts to prepare solanoeclepin A and kainic acid, modifications of which were previously mentioned (Schemes 6.31 and 6.33) [89,91]. The chain length of the alkenyl group is responsible for the desired endo-addition mode.…”

Regioselective SN2' Mitsunobu reaction of Morita–Baylis–Hillman alcohols: A facile and stereoselective synthesis of α-alkylidene-β-hydrazino acid derivatives

“…Mortia–Baylis–Hillman (MBH) alcohol 1 were prepared according to literature procedures [46–47]. Benzyl 2-(hydroxymethyl)buta-2,3-dienoate ( 6 ) is a known compound and was prepared according to a literature [48]. Reagents from commercial sources were used without further purification.…”

Total Synthesis of Aquatolide

“…The real structure of aquatolide ( 2 ) caught our attention because we recently developed a synthesis of bicyclic lactones of type 5 through irradiation of allenic butenolides of type 4 (Scheme ). This latter research is related to our work on a synthetic approach toward the potato cyst hatching agent solanoeclepin A (Figure ), which also contains the rare bicyclo[2.1.1]­hexane skeleton as present in 2 .…”