Biography:

In the past A. Srikrishna has collaborated on articles with Goverdhan Mehta. One of their most recent publications is A novel, versatile synthetic approach to linearly fused tricyclopentanoids via photo-thermal olefin metathesis. Which was published in journal Tetrahedron.

More information about A. Srikrishna research including statistics on their citations can be found on their Copernicus Academic profile page.

A. Srikrishna's Articles: (13)

A novel, versatile synthetic approach to linearly fused tricyclopentanoids via photo-thermal olefin metathesis

AbstractFifteen examples of a new, speedy and general approach to linearly fused tricyclopentanoids bearing the tricyclo[6.3.0.02,6]undecane (triquinane) frame of high contemporary interest is delineated. The key concept in our synthetic sequence to triquinanes is the novel photo-thermal olefin metathesis of cheap, abundantly available Diels-Alder adducts of 1,3 cyclopentadienes and p-benzoquinones. Thus photolysis of endo-tricyclo[6.2.1.02,7] undeca-4,9-dien-3,6-diones (9a–9j, 13a,b) furnished pentacyclo [5.4.0.02,6.03,10.05,9]undecan-8,11-diones (10a–10j, 14a,b), which on thermal fragmentation of the cyclobutane ring gave cis, syn, cis-tricyclo [6.3.0.02,6]undeca-4,9-dien-3,11-diones (11a–11j, 15a,b in just three steps and in exceptionally good yields. A few interesting transformations of the readily available parent bis-enone 11a which indicates its wider uses in syntheses, are described. Finally, a smooth thermal isomerisation of cis, syn, cis-bis-enones to cis, anti, cis-bis-enones is reported, which further enhances the scope and versatility of our synthetic theme.

A radical cyclisation based strategy to cuparenoids; synthesis of (±)-α-cuparenone, (±)-epilaurene and laurenes

AbstractMercuric acetate catalysed one pot Claisen rearrangement of the cinnamyl alcohol 5, generated the pent-4-enal 9, which on homologation resulted the hex-5-enal 10. Radical cyclisation of the radical anion derived from 10, followed by oxidation provided the ketone mixture 4, a known precursor to the sesquiterpenes (+)-α-cuparenone (1), (+)-epilaurene (3) and laurene (2).

Radical cyclization strategies to terpenoids; syntheses of (±)-β-cuparenone, (±)-laurene and epilaurenes

AbstractRadical cyclization of the bromide 8, obtained in 5 steps from the ketone 9, furnished exclusively 14via 6-endo trig cyclization with out any observable amount of 5-exo trig product 1. 5-Exo dig radical cyclizatlon of the bromo acetate 23, prepared from 18via the aldehyde 21, followed by routine transformations furnished the cyclopentenone 26, an immediate precursor to β-cuparenone (2). Similarly, total synthesis of laurenes 4 and 5 was achieved via the 5-exo dig radical cyclization of the xanthate 28, obtained from the aldehyde 21.

Structure revision of HM-3, an aromatic sesquiterpene isolated from the phytopathogenic fungus Helicobasidium mompa. First total syntheses of HM-3 and HM-4

AbstractThe first total syntheses of HM-3 and HM-4, aromatic sesquiterpenes isolated from the phytopathogenic fungus Helicobasidium mompa, have been accomplished. The structure assigned to the sesquiterpene HM-3 was found to be incorrect by total synthesis. A Claisen rearrangement–RCM reaction based strategy was employed for the total synthesis of the aromatic sesquiterpene HM-4 (cuparene-1,2-diol), which on selective monoacetylation established the structure of HM-3, a cuparene derivative.

A stereoselective total synthesis of (−)-seychellene

AbstractA stereoselective total synthesis of the tricyclic sesquiterpene (−)-seychellene, starting from (R)-carvone via (R)-3-methylcarvone has been accomplished, employing a combination of intermolecular Michael addition–intramolecular Michael addition sequence, a stereoselective hydrogenation, and an intramolecular alkylation reaction.

Enantiospecific approach to the tricyclic core structure of tricycloillicinone, ialibinones, and takaneones via ring-closing metathesis reaction

AbstractEnantiospecific synthesis of the tricyclic core structure present in the biologically active natural products tricycloillicinone, ialibinones, and takaneones, starting from the readily available campholenaldehyde employing a transannular RCM reaction as the key step, has been accomplished.

Total synthesis of (±)-laurene and epilaurene by radical cyclisation reaction

AbstractTotal synthesis of (±)-laurene and epilaurene, via the radical cyclisation of the xanthate (11) derived from the acetylenic alcohol (10), is described.

Olefin metathesis in polycyclic frames 1. A new way to cis, syn, cis - tricyclopentanoids (acs-C11-triquinanes)

AbstractA novel olefin metathesis sequence permits ready access to functionalised cis, syn, cis-tricyclo [6.3.0.02,6] undecane based bis-enones. These bis-enones have been shown to undergo cage cyclisation in sunlight with remarkable ease and efficiency.

An efficient construction of a C3-symmetric macrocycle by head to tail cyclotrimerization of an unsymmetrical diene via a sequence of highly regio- and stereoselective metathesis reactions☆

AbstractA sequence of highly regio- and stereoselective intermolecular metatheses followed by ring-closing metathesis of an 1-allyl-3-(3-butenyl)cyclohexanol led to a C3-symmetric head to tail cyclic trimer; a 24-membered macrocycle containing three inward directed hydroxyl groups creating a hydrophilic cavity.

A biogenetically patterned enantiospecific synthesis of allopupukeanones

AbstractThe first enantiospecific synthesis of allopupukeanones has been accomplished starting from 6-methylcarvone. A biogenetically patterned rearrangement of a pupukeanane to allopupukeanane was employed as the key step.

Pyridinium chlorochromate mediated oxidative cyclisation of sterically crowded γ,δ-unsaturated alcohols

AbstractPyridinium chlorochromate (PCC) mediated oxidative cyclisation of sterically crowded γ,δ-unsaturated alcohols (primary, secondary, allylic, benzylic as well as tertiary) is described.

Enantiospecific synthesis of (+)-pinguisenol, (+)-pinguisen-10-one and (−)-pinguisen-8,10-dione☆

AbstractThe first enantiospecific total synthesis of the sesquiterpene (+)-pinguisenol, the optical antipode of the natural product, and the analogues (−)-pinguisen-10-one and (+)-pinguisen-8,10-dione, starting from R-carvone are described.

Synthesis of chiral bicyclo[4.3.1]decanes via an intramolecular carbonyl ene-reaction

AbstractSynthesis of chiral bicyclo[4.3.1]decanes via an intramolecular acid catalysed type II ene reaction of chiral (5-isopropenylcyclohex-2-enyl)acetaldehydes derived from (R)-carvone is described.

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