A Practical Synthesis of Cyclohexyl-Based Chiral Auxiliaries from Limonene Oxide

Comins, Daniel L.; Guerra‐Weltzien, L.; Salvador, James M.

doi:10.1055/s-1994-23069

Cited by 21 publications

(9 citation statements)

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“…The authors developed a new chiral auxiliary (1S,2R,4S)-2-(1-methyl-1-phenylethyl)-4-(2-propyl)-cyclohexanol, (−)-CPC 2c (Scheme 2), which is prepared from limonene oxide. 75 This chiral auxiliary is often more effective than TCC derivatives due to having an isopropyl group at the cyclohexyl ring. 76 The pyridinium salt 3c with CPC was used for the synthesis of indolizidine alkaloid (+)-209D 77 and (−)-perhydrohistrionicotoxin.…”

Section: Nucleophilic Additionmentioning

confidence: 86%

“…The authors developed a new chiral auxiliary (1 S ,2 R ,4 S )-2-(1-methyl-1-phenylethyl)-4-(2-propyl)-cyclohexanol, (−)-CPC 2c (Scheme ), which is prepared from limonene oxide . This chiral auxiliary is often more effective than TCC derivatives due to having an isopropyl group at the cyclohexyl ring .…”

Section: Reactions Involving Cationic Intermediates or Transition Statesmentioning

confidence: 99%

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Cation−π Interactions in Organic Synthesis

2018

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The cation−π interaction is an attractive noncovalent interaction between a cation and a π system. Due to the stronger interaction energy than those of the other π interactions, such as π–π and CH−π interactions, the cation−π interaction has recently been recognized as a new tool for controlling the regio- and stereoselectivities in various types of organic reactions. This review attempts to cover a variety of organic reactions controlled by cation−π interactions, which includes not only recent examples but also those reported before the term “cation−π interaction” was defined in 1990. This review will provide comprehensive knowledge on the role of cation−π interactions in organic synthesis.

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Section: Nucleophilic Additionmentioning

confidence: 86%

Section: Reactions Involving Cationic Intermediates or Transition Statesmentioning

confidence: 99%

Cation−π Interactions in Organic Synthesis

2018

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“…Although the separation of both cis-and trans-1,2-epoxylimonene can be achieved by careful spinning-band distillation 16 , this is a difficult and slow task and more practical methods of obtaining the pure trans-epoxide involve selective chemical transformation of the 1:1 mixture of isomers 10 or reaction of limonene with NBS/H 2 O followed by base treatment 17 . Moreover, trans-1,2-epoxylimonene is more reactive than cis and so it is selectively opened on nucleophilic additions to the mixture of cis-and trans-1,2-epoxylimonene 18 .…”

Section: Resultsmentioning

confidence: 99%

Cohalogenation of limonene, carvomenthene and related unsaturated monoterpenic alcohols

Sanseverino

Silva

Jones

et al. 2000

J. Braz. Chem. Soc.

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A coalogenação de (R)-limoneno e (R)-carvomenteno com I 2 /H 2 O/Cu(OAc) 2 ·H 2 O em dioxano aquoso seguida por tratamento em meio básico produz estereoespecificamente os transepóxidos correspondentes. Já essa mesma metodologia de coalogenação aplicada a álcoois monoterpênicos insaturados estruturalmente relacionados produz derivados do pinol [a partir de (5R)-cis-carveol e (S)-α-terpineol] ou então iodoidrinas [a partir de (S)-álcool perílico e (5R)-Cohalogenation of (R)-limonene and (R)-carvomenthene with I 2 /H 2 O/Cu(OAc) 2 ·H 2 O in aqueous dioxane followed by base treatment produced stereospecifically the corresponding trans-epoxides. Same methodology of cohalogenation applied to related monoterpenic unsaturated alcohols produced pinol derivatives [from (5R)-cis-carveol and (S)-α-terpineol] or iodohydrins [from (S)-perillyl alcohol and (5R)-trans-carveol].

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“…A drawback to this method is the difficulty of removing the chiral auxiliary due to the sensitive nature of the dihydropyridine system, although it could be removed following reduction to the enantioenriched piperidine later used in the synthesis of (-)-Nmethylconiine. 27 Several reactions were performed (Table 5) and the yields obtained ranged from 58 to 87%. The diastereomeric excess was determined by HPLC or 1 H NMR analyses and reached high values, namely 92% for the reaction with 4tolylmagnesium bromide ( Table 5, entry 8).…”

Section: Nucleophilic Addition To Pyridines and Pyridinium Saltsmentioning

confidence: 99%