Synthesis of cembrene. 14-Membered ring diterpene

Synthese von (−)‐(R)‐Nephthenol und (−)‐(R)‐Cembren A

“…Dabei wurden fur die Bildung des 14gliedrigen C-Ringes verschiedene Wege eingeschlagen: Die Bildung des Ringes gelang u. a. mit Hilfe der Ni(CO),-induzierten Verkniipfung eines offenkettigen Dibromides [6] und durch anionisch [7] wie auch durch kationisch [8] induzierte Cyclisierungen. Andere Arbeiten berichten von einer Cyclisierung mittels Horner-Emmom-Reaktion [9], Bildung des C-Ringes mittels wiederholter Cope-Umlagerungen [ 101 oder durch 2,3-Wittig-Umlagerung [l 11.…”

Natural Resins of Art and Archaeology Their Sources, Chemistry, and Identification

“…The Haploxylon pine resins also contain the same compounds mainly but most of them also contain the macrocyclic hydrocarbon thunbergene (cembrene) (XVIII). [19] gives extensive references to occurrences. Some labdane compounds occur in the resins of a few species, sometimes in large amounts, but these are not usually of the polymerizable diene type.…”

“…Studies inConservation, 22 (1977),[12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31] Natural resins of art and archaeology. Their sources, chemistry, and identification…”

Methods Utilizing First-Row Transition Metals in Natural Product Total Synthesis

“…Corey and co-workers have also synthesized non-natural carbon macrocycles up to 18 members in size by both single C–C bond formation and oligomerization. , Macrocyclic lactones are also accessible through this strategy . Humulene has been synthesized a number of times since Corey’s first report, including several alternative approaches by Corey himself. − For the synthesis of other natural products, intramolecular allylic halide coupling has also been employed as a key step in Corey’s total synthesis of d , l -elemol, Dauben’s total synthesis of cembrene, , Pattenden’s total synthesis of casbene, , and (with benzylic halides) Iyoda’s total synthesis of rioccardin B …”

“…88 Humulene has been synthesized a number of times since Corey's first report, including several alternative approaches by Corey himself. 89−95 For the synthesis of other natural products, intramolecular allylic halide coupling has also been employed as a key step in Corey's total synthesis of d,l-elemol, 96 Dauben's total synthesis of cembrene, 97,98 Pattenden's total synthesis of casbene, 99,100 and (with benzylic halides) Iyoda's total synthesis of rioccardin B. 101 The synthetic utility of reductive halide coupling is clearly demonstrated in Corey's synthesis of α-santalene (4-2), where a prenyl group is introduced as a late-stage modification (Scheme 4).…”