Camphor Derivatives in Asymmetric Cycloadditions and Rearrangements

Langlois, Y.; Kouklovsky, Cyrille

doi:10.1055/s-0029-1218302

Cited by 18 publications

(12 citation statements)

References 24 publications

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“…In the subfield of covalent organocatalysis, there are only a few reports of camphor‐derived catalysts. Those are mainly five‐ and six‐membered cyclic sulfonyl hydrazine derivatives prepared from camphor sulfonic acid 11–14. However, there are also more noncovalent camphor‐derived organocatalysts, the bulk of them comprised of pyrrolidinyl–camphor–derived bifunctional organocatalysts, where both camphor and pyrrolidine chiral frameworks, connected with an appropriate linker, act in synergy 15–24.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and structural elucidation of novel camphor‐derived thioureas

et al. 2012

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Nine novel (+)-camphor-derived thioureas have been prepared. 3-((Dimethylamino)methylene)camphor (2) served as the common precursor for the preparation of both, 2-thiourea 15-20 and 3-thiourea functionalized camphor derivatives 6, 7/7', respectively. Starting from 2, the latter were prepared in two or three steps whereas the former in five steps, respectively. Configuration of all novel compounds has been meticulously determined using NMR techniques and/or single crystal X-ray crystallography.

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Section: Introductionmentioning

confidence: 99%

Synthesis and structural elucidation of novel camphor‐derived thioureas

et al. 2012

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“…Few reviews in organocatalytic [4 + 2] cycloadditions including iminium activation [14], Brønsted-acid and Brønsted-base catalysis [15], camphor derivatives catalysis [16] as well as bifunctional organic catalysis [17] have been reported [18]. The first highly enantioselective organocatalytic Diels-Alder reaction was reported by MacMillan and his co-workers in the reaction of a,b-unsaturated aldehydes 28 and dienes, e.g., cyclopentadiene 29, Schemes 3.8 and 3.9 [19].…”

Section: [4 + 2] and Diels-alder Reactionmentioning

confidence: 99%

Organocatalyzed Cycloadditions

Hong¹

2011

Enantioselective Organocatalyzed Reactions II

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Cycloadditions have been for a long time one of the most useful reactions in organic synthesis. Recently, the ability to promote the reactions by organocatalysts further expands the realm of its synthetic application. This review aims to highlight the recent advances in this area with particular emphasis on the asymmetric cycloaddition promoted by organocatalysts. IntroductionGenerating selectively the maximum number of bonds and stereogenic centers in a one-step (or one-pot) reaction constitute to be of key interest in synthetic chemistry. Among many methodologies for the objective, cycloaddition stand out. While searching for a better and tunable catalyst able to promote a wide spectrum of cycloaddition, organocatalysis was revealed as a powerful tool for efficient operations and many other merits, e.g., high stereoselectivity, moisture and air resistant, environmental benign and user friendly. Surprisingly, organocatalytic synthesis was virtually dominant for few decades until just the turn of this century [1]; nevertheless, it soon become the focal point, and it has occupied an important chapter in the modern synthetic chemistry [2]. In a very short period of time, more than hundred review articles of organocatalytic reactions were reported, and the papers are continuing to appear for summarizing up the thriving and robust subject. Several theoretical studies, including the computational Intramolecular CycloadditionsIn 2005, MacMillan reported an enantioselective organocatalytic intramolecular Diels-Alder reaction (IMDA) of a,b-unsaturated aldehyde and diene, as well as the application in the asymmetric synthesis of solanapyrone D (6), Scheme 3.1 [5]. Later, Danishefsky and Christmann individually reported the total synthesis of UCS1025A (9) by coupling reaction with MacMillan aldehyde (8) [6]. The malimide analogue 10 of the telomerase inhibitor UCS1025A (9) was also prepared by Christmann et al. by modified MacMillan's conditions (10 mol% catalyst loading in nitromethane, affording 74% yield and >99% ee after a sequence of recrystallization and oxidation), Scheme 3.2 [7]. In 2003, an interesting intramolecular organocatalytic [3 + 2] dipolar cycloaddition of an enynoate (19) catalyzed by PBu 3 was developed by Krische and his coworker in the total synthesis of (±)-hirsutene (21), Scheme 3.6 [12]. The intramolecular phosphane-catalyzed [3 + 2] dipolar cycloaddition provides a concise approach to the linear triquinane hirsutene, whereby three contiguous stereogenic centers are created and controlled in a single reaction step.A light-driven enantioselective organocatalysis intramolecular [2 + 2] photocycloaddition of quinolone (24) [4 + 2] cycloadditions. The enantioselectivity was rationalized by the fact that selective formation of the (E)-iminium isomer to avoid nonbonding interactions between the substrate olefin and the geminal methyl substituents and the benzyl group on the catalyst framework which effectively shields the re face of the dienophile, leaving the si face exposed to cycloadditio...

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“…1,3-Diiodo-5,5-dimethylhydantoin (DIH) was proposed as effective catalyst for reactions of amino alcohols with aldehydes [169]; one-pot synthesis of arylsubstituted dihydrooxazoles using substituted benzoyl chlorides was reported [170]; microwave activation of such syntheses was considered in [52]. Methods were developed for the synthesis of various functionalized dihydrooxazoles [171][172][173][174], including those containing sulfonamide and carboxamide groups (which are capable of catalyzing asymmetric Diels-Alder reactions) [175,176], and new camphor derivatives for asymmetric cycloaddition and rearrangements [177]. Some dihydrooxazolyloxiranes [178,179] have found application in polymer chemistry [180] and in the synthesis of practically important polyfunctional compounds 142 [179] (Scheme 84).…”

Section: 5-dihydro-13-oxazolesmentioning

confidence: 99%