Synthesis of 8-methylnonane-1,6,7-trien-4-one and related allenes as potentially useful synthetic precursors

Abstract

ABSTRACT. The allenic ketone 8-methylnonane-1,6,7-trien-4-one and related allenes have been synthesized from simple commercially available materials. Since allenes analogous to 8-methylnonane-1,6,7-trien-4-one have previously been transformed to substituted bicyclo[3.3.0]octanones via corresponding bicyclo[3.2.0]heptanones, it is anticipated that the present allenic ketone may also undergo similar transformations. Substituted bicyclo[3.3.0]octanones are known synthetic precursors of tricyclic sesquiterpenes. Thus, 8-methylnonane-1,6,7-trien-4-one presents itself as a possible precursor for the synthesis of tricyclopentanoid ring system present in sesquiterpenes such as hirsutene and ∆ 9 (12) -capnellene.

Total Synthesis of Ikoamide, a Highly N-Methylated Antimalarial Lipopeptide

“…Our synthesis of the chiral dimethoxyocatanoic acid 3 is summarized in Scheme . The synthesis started with the Corey–Seebach reaction of ( R )-1,2-epoxypentane 4 with 2-allyl-1,3-dithiane to obtain alcohol 14 . The dithiane hydrolysis of 14 gave ketone 15 , which was further converted into the known diol 16 by Evans–Saksena reduction .…”

Direct Cross‐Couplings of Propargylic Diols

“…1,1,4,4-tetraphenylbut-2-yne-1,4-diol, 4 1,1'-(ethyne-1,2-diyl)bis(cyclopentan-1-ol), 5 1,1diphenylbut-2-yne-1,4-diol, 6 and 4-methylpent-2-yne-1,4-diol 7 were prepared according to literature procedures.…”

“…4 Accordingly, numerous techniques to synthesize the 1,3-diene motif featuring various substitution patterns have been devised. [5][6][7][8][9][10][11][12][13] Cross-coupling reactions grant facile access to many butadiene substitution patterns. Thus, Böhmer and Grigg employed two-fold Stille or Suzuki-Miyaura reactions to convert propargylic dicarbonates into 2,3-diaryl-1,3-butadienes carrying up to two additional substituents (Scheme 1a).…”

Syntheses of bicyclo[3.3.0]octanes and bicyclo[4.3.0]nonanes by ring expansion of isopropylidenecyclobutanes

“…[8][9][10][11][12] Despite several existing methods, the structural variety of these compounds still calls for new practical procedures to be developed. 13 While working on a synthesis of the insect pheromone component lineatin, we…”