A convergent synthesis of triquinane sesterterpenes.

The present strategy enables a straightforward approach to the natural linear triquinane skeleton, as demonstrated by concise and step economical syntheses of hirsutene and 1-desoxy-hypnophilin, whereby the linear triquinane core is diastereoselectively established in one manipulation with correct placement of all stereocenters, including two quarternary centers.

A new approach to all—cis triquinane synthesis and a …

Triquinane sesquiterpenes. An iterative, highly stereocontrolled synthesis of (.+-.)-silphinene
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| A new synthesis of all-cis triquinanes is presented

The paper describes the first total synthesis of (+/-)-1-desoxyhypnophilin, a linear triquinane from the East African mushroom Lentinus crinitus which displays promising antimicrobial activity. A key feature is the use of a ring closing metathesis reaction with a tertiary allylic alcohol, in conjunction with a PCC induced oxidative rearrangement, to construct a cyclopentenone.

Stereocontrolled total synthesis of the triquinane …

25. D. P. Curran and D. M. Rakiewicz, Radical-Initiated Polyolefinic Cyclizations in Linear Triquinane Synthesis. Model Studies and Total Synthesis of ()-Hirsutene. Invited paper for Tetrahedron Symposium in Print on Radicals in Organic Synthesis, B. Giese, Ed. Tetrahedron 1985, 41, 3943.

Triquinane synthesis essay - The Pandora Jewellery Blog
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involved in the synthesis of a linear triquinane.

AB - Unsaturated acyloxazolidinones and α'-silyloxy enones were found to be effective substrates in nickel-catalyzed organozinc-promoted cyclizations. Both groups served as convenient enoate equivalents, whereas methyl enoates themselves were inefficient substrates. A five-step procedure for the conversion of dimethylcyclopentenone into a highly functionalized angular triquinane was developed utilizing this observation. The key step of the procedure involves a nickel-catalyzed reductive cyclization/Dieckmann condensation sequence involving a cyclic enone tethered to an unsaturated acyloxazolidinone or α'-silyloxy enone. The method was applied in a formal synthesis of pentalenene, pentalenic acid, and deoxypentalenic acid.

Structure and synthesis of .beta.-vetivone

AB - Terpenoids are a large structurally diverse group of natural products with an array of functions in their hosts. The large amount of genomic information from recent sequencing efforts provides opportunities and challenges for the functional assignment of terpene synthases that construct the carbon skeletons of these compounds. Inferring function from the sequence and/or structure of these enzymes is not trivial because of the large number of possible reaction channels and products. We tackle this problem by developing an algorithm to enumerate possible carbocations derived from the farnesyl cation, the first reactive intermediate of the substrate, and evaluating their steric and electrostatic compatibility with the active site. The homology model of a putative pentalenene synthase (Uniprot: B5GLM7) from Streptomyces clavuligerus was used in an automated computational workflow for product prediction. Surprisingly, the workflow predicted a linear triquinane scaffold as the top product skeleton for B5GLM7. Biochemical characterization of B5GLM7 reveals the major product as (5S,7S,10R,11S)-cucumene, a sesquiterpene with a linear triquinane scaffold. To our knowledge, this is the first documentation of a terpene synthase involved in the synthesis of a linear triquinane. The success of our prediction for B5GLM7 suggests that this approach can be used to facilitate the functional assignment of novel terpene synthases.

Photocyclization-fragmentation route to linear …

N2 - Terpenoids are a large structurally diverse group of natural products with an array of functions in their hosts. The large amount of genomic information from recent sequencing efforts provides opportunities and challenges for the functional assignment of terpene synthases that construct the carbon skeletons of these compounds. Inferring function from the sequence and/or structure of these enzymes is not trivial because of the large number of possible reaction channels and products. We tackle this problem by developing an algorithm to enumerate possible carbocations derived from the farnesyl cation, the first reactive intermediate of the substrate, and evaluating their steric and electrostatic compatibility with the active site. The homology model of a putative pentalenene synthase (Uniprot: B5GLM7) from Streptomyces clavuligerus was used in an automated computational workflow for product prediction. Surprisingly, the workflow predicted a linear triquinane scaffold as the top product skeleton for B5GLM7. Biochemical characterization of B5GLM7 reveals the major product as (5S,7S,10R,11S)-cucumene, a sesquiterpene with a linear triquinane scaffold. To our knowledge, this is the first documentation of a terpene synthase involved in the synthesis of a linear triquinane. The success of our prediction for B5GLM7 suggests that this approach can be used to facilitate the functional assignment of novel terpene synthases.