- Conversion of Campholene- to Necrodane-Type Monoterpenes. A Short Stereoselective Synthesis of (-)-(R,R)-β-Necrodol and its Three Stereoisomers
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Application of a stereoselective Prins/retro-Prins rearrangement sequence from (-)-(R)-campholenyl acetate ((-)-4) opens a new access to the naturally occuring (-)-(R,R)-β-necrodol ((-)-1 and its three stereoisomers with high optical purity.
- Schulte-Elte, Karl H.,Pamingle, Herve
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- High diastereoselectivity in Claisen rearrangement in a sterically congested cyclopentane system. Total synthesis of (±)-β-necrodol
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Total synthesis of the monoterpene β-necrodol has been accomplished. The key step involves an ortho-ester Claisen rearrangement in a highly sterically congested cyclopentane derivative resulting in a high level of 1,3-trans diastereoselection. A novel photo-induced decarboxylation of the obtained γ,δ-unsaturated acid afforded β-necrodol.
- Samajdar, Susanta,Ghatak, Anjan,Banerjee, Shyamapada,Ghosh, Subrata
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- Synthesis and bioassay of racemic and chiral trans -α-Necrodyl Isobutyrate, the sex pheromone of the grape mealybug pseudococcus maritimus
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A concise synthesis of the racemic form of the female-produced pheromone of the grape mealybug was developed. The synthesis was readily adapted to production of both enantiomers of the pheromone via lipase-catalyzed kinetic resolution of an intermediate in the synthesis. Replicated field trials revealed that, contrary to a preliminary report, the (R,R)- rather than the (S,S)-enantiomer is the attractive stereoisomer. Lithium aluminum hydride reduction of the insect-produced compound to α-necrodol followed by analysis on a chiral stationary phase GC column showed that the insect-produced material was actually an 85:15 mixture of the (R,R)- and (S,S)-enantiomers. The racemic form of the pheromone was highly attractive to male mealybugs, and in one of two field bioassays, the racemic material was significantly more attractive than the pure (R,R)-enantiomer, suggesting that the (S,S)-enantiomer might act synergistically.
- Zou, Yunfan,Daane, Kent M.,Bentley, Walt J.,Millar, Jocelyn G.
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- Stereocontrolled total synthesis of (±)-β-necrodol
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A total synthesis of racemic β-necrodol is described using an ortho- ester Claisen rearrangement as the key step to dictate a high level of trans- 1,3-diastereoselection on a cyclopentane derivative.
- Samajdar, Susanta,Ghatak, Anjan,Ghosh, Subrata
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p. 4401 - 4402
(2007/10/03)
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- Defense Mechanisms of Arthropods. 84. Synthesis of (-)-α-Necrodol and (-)-β-Necrodol: Novel Cyclopentanoid Terpenes from a Carrion Beetle
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Syntheses of (-)-α-necrodol (1) and (-)-β-necrodol (2) from (+)-phenylcamphoric acid (7a) are described.In addition, several related compounds, (+)-epi-α-necxrodol (3), (+)-epi-β-necrodol (4), and (+)-γ-necrodol (5), have been prepared.The absolute configuration of natural α-necrodol has been established as 3R,5R by comparison of its (+)-α-methoxy-α-(trifluoromethyl)phenylacetyl ester with the ester derived from synthetic 1.
- Jacobs, Robert T.,Feutrill, Geoffrey I.,Meinwald, Jerrold
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p. 4051 - 4062
(2007/10/02)
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- A Synthesis of β-Necrodol Via A Palladium Catalyzed Reductive Enyne Cyclization
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The Pd catalyzed reductive enyne cyclization provides an approach to control 1,3-diastereoselectivity and thereby provides a five step synthesis of β-necrodol, a key substituent of the defensive secretion of the red-lined carrion beetle.
- Trost, Barry M.,Braslau, Rebecca
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p. 1231 - 1234
(2007/10/02)
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