Structure elucidation of laureoxanyne, a new nonisoprenoid C15 enyne, using lactoperoxidase

Structure Determination of a Chloroenyne from Laurencia majuscula Using Computational Methods and Total Synthesis

“…21 As noted above, a biosynthesis of notoryne 3 was first proposed by Suzuki and by Fukuzawa and Murai (Figure 1a). 21,24 Previously, the Oxford group had prepared the 2,2′-bifuranyl 28 (Scheme 1), with the necessary stereochemical arrangement for ready conversion into notoryne ( Z )- 3a . Additionally, the Seoul group had demonstrated a number of biomimetic syntheses of halogenated natural products from Laurencia spp., including the synthesis of the 2,2′-bifuranyl natural products ( Z )- and ( E )-elatenyne 15d and laurendecumenyne B.…”

“…Algae of the genus Laurencia produce a vast array of structurally diverse C 15 halogenated natural products. Elatenyne, 19,20 notoryne ( 3 ), 21 laurendecumenyne B, 20,22 laurefurenynes A and B, 23 and the above chloroenyne from L. majuscula 2 (17) are currently the only 2,2′-bifuranyl natural products that have been isolated from Laurencia spp. Notoryne 3 was the first of these 2,2′-bifuranyls to be isolated, and its structure was determined through extensive chemical degradation and by comparison with chemical degradation products of laurencin.…”

Biosynthesis of the C15-acetogenin laurepoxide may involve bromine-induced skeletal rearrangement of a Δ4-oxocene precursor

“…In an elegent series of studies, Fukuzawa and Murai showed that haloether deacetyllaurencin, upon exposure to lactoperoxidase, halide and hydrogen peroxide, was transformed into a diverse array of other natural products including laureoxanyne, laurefucin, and notoryne (Scheme 1a). 2–4 These findings are strongly suggestive of the existence of key transient bromonium species 1 , which can undergo an intramolecular bromoetherification and subsequent oxonium ylide-induced reactions to yield the observe products (Scheme 1a). Structural variants bromofucin 5 and chlorofucin 6 are also believed to be accessed via analogous bromonium intermediates.…”

Progress in the Chemistry of Organic Natural Products 102

“…These can be roughly divided into four subgroups, namely: (1) those containing one tetrahydrofuran ring ; (2) those containing two isolated tetrahydrofuran rings (730)(731)(732)(733)(734)(735)(736)(737)(738); (3) those containing two fused tetrahydrofuran rings (739)(740)(741)(742)(743)(744)(745)(746)(747)(748)(749)(750)(751)(752)(753)(754)(755)(756)(757); and (4) maneonenes and isomaneonenes containing three tetrahydrofuran rings (758)(759)(760)(761)(762)(763)(764)(765)(766)(767)(768)(769). These can be roughly divided into four subgroups, namely: (1) those containing one tetrahydrofuran ring ; (2) those containing two isolated tetrahydrofuran rings (730)(731)(732)(733)(734)…”

“…The structure of elatenyne (735) attracted the attention of many research groups, who, utilizing chemical and computational methods, finally succeeded in synthesizing the molecule corresponding to the spectroscopic data of the natural product, and revising the proposed structure to that of a 2,2 0 -bis-tetrahydrofuran derivative. Acetogenins containing two fused tetrahydrofuran rings can be differentiated into those with either a 2,6-dioxabicyclo[3.3.0] octane (739)(740)(741)(742)(743)(744)(745)(746)(747)(748)(749)(750)(751)(752) or a 2,5-dioxabicyclo[2.2.1]heptane (753)(754)(755)(756)(757) substructure. A similar revision was made to the structure of laurendecumbenyne B (733), which was established only on the basis of comparison of NMR data with those originally assigned for 735 [612].…”