- Enantiospecific Total Syntheses of (+)-Hapalindole H and (?)-12-epi-Hapalindole U
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Enantiospecific total syntheses of (+)-hapalindole H and (?)-12-epi-hapalindole U as well as the formal syntheses of (+)-hapalindole Q and (+)-12-epi-fischerindole U isothiocyanate have been described. Key steps of our approach feature expedient, highly regio- and diastereoselective Lewis acid catalyzed Friedel–Crafts reaction of indole with cyclic allylic alcohols and intramolecular reductive Heck reaction. Efficiency of the synthetic route also relies on an alkynyl aluminate complex driven regioselective nucleophilic epoxide opening from a sterically hindered site.
- Dethe, Dattatraya H.,Das, Saikat,Kumar, Vijay B.,Mir, Nisar A.
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supporting information
p. 8980 - 8984
(2018/06/04)
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- Protecting group free enantiospecific total syntheses of structurally diverse natural products of the tetrahydrocannabinoid family
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A simple, highly diastereoselective, Lewis acid catalyzed Friedel-Crafts coupling of a cyclic allylic alcohol with resorcinol derivatives has been developed. The method was applied for the enantiospecific total syntheses of structurally diverse natural products such as machaeriol-D, Δ8-THC, Δ9-THC, epi-perrottetinene and their analogues. Synthesis of both natural products and their enantiomers has been achieved with high atom economy, in a protecting group free manner and in less than 6 steps, the longest linear sequence, in a very good overall yield starting from R-(+) and S-(-)-limonene.
- Dethe, Dattatraya H.,Erande, Rohan D.,Mahapatra, Samarpita,Das, Saikat,Kumar B., Vijay
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supporting information
p. 2871 - 2873
(2015/03/03)
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- Enantiospecific total syntheses and assignment of absolute configuration of cannabinol-skeletal carbazole alkaloids murrayamines-O and -P
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First enantiospecific total syntheses of the cannabinol-skeletal carbazole alkaloids murrayamines-O and -P isolated from root barks of Murraya euchrestifoli, have been accomplished by highly diastereoselective, Lewis acid catalyzed coupling reactions of commercially available monoterpenes with carbazole derivative, which in addition to confirming the structure also established the absolute configuration of the natural products. Synthesis of both natural products and their enantiomers was achieved with high atom economy, in a protecting-group free manner and in six steps longest linear sequence from commercially available aniline derivative and verbenol.
- Dethe, Dattatraya H.,Das, Saikat,Dherange, Balu D.,Mahapatra, Samarpita
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supporting information
p. 8347 - 8350
(2015/06/02)
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- 3-Alkyl-p-menthan-3-ol derivatives: synthesis and evaluation of their physiological cooling activity
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Different 3-alkyl-p-methan-3-ol derivatives provide a strong physiological cooling effect with potential application as food and cosmetic additives. In order to investigate the influence of the chemical structure on the cooling sensation, the stereoselective syntheses of 29 different 3-alkyl-p-methan-3-ol derivatives were accomplished. All the compounds obtained are odorless and were evaluated by taste, considering two sensations: a cooling effect and bitterness. The results of this structure-activity relationship study highlight that compounds with a (1R,4S)-configuration are the isomers with the more intense cooling effect and lower bitterness. In addition, the structure of the 3-alkyl chain affected the latter properties. Increasing the chain length over two carbon atoms does not change the cooling power, but enhances the bitterness with the additional feature that the branched isomers are considerably more bitter than the linear ones. Overall, the 3-alkyl-p-menthan-3-ol isomers with the best quality in terms of high cooling power and low bitterness are (1R,4S)-3-(hydroxymethyl)-p-menthan-3-ol diastereoisomers (-)-38 and (-)-42.
- Fuganti, Claudio,Joulain, Daniel,Maggioni, Francesco,Malpezzi, Luciana,Serra, Stefano,Vecchione, Andrea
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body text
p. 2425 - 2437
(2009/04/06)
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- Lipase-catalyzed resolution of p-menthan-3-ols monoterpenes: Preparation of the enantiomer-enriched forms of menthol, isopulegol, trans- and cis-piperitol, and cis-isopiperitenol
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A study on the enzymic resolution of the most common p-menthan-3-ol monoterpene isomers is described. Enantioenriched alcohols 1, 5, 10, 11 and 12 are obtained by means of the lipase-mediated kinetic acetylation of the corresponding racemic materials. The stereochemical aspects of the enzymic process have been investigated. We found that the structural features of the starting p-menthan-3-ol as well as the kind of lipase used, impacted strongly on the enantioselectivity of the resolution. The potentialities of this approach for preparative purposes are discussed.
- Serra, Stefano,Brenna, Elisabetta,Fuganti, Claudio,Maggioni, Francesco
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p. 3313 - 3319
(2007/10/03)
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- Synthesis of (+/-)-Isopiperitenol by Fluoride Ion Mediated Cyclization of Allylsilane Moiety Incorporated in Terpene Aldehydes
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Fluoride ion mediated cyclization of aldehydes (1 and 2) having regioisomeric allylsilane functionalities gave a mixture of cis- and trans-isopiperitenol (3).The aldehydes (1) reacted faster and showed better stereoselectivity than the regioisomeric aldeh
- Nakamura, Hideshi,Oya, Toyohisa,Murai, Akio
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p. 929 - 931
(2007/10/02)
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