Total Synthesis of the <i>Kopsia</i> <i>lapidilecta </i>Alkaloid (±)-Lapidilectine B

Pearson, William H.; Mi, Yuan; Lee, Ill Young; Stoy, Patrick

doi:10.1021/ja016007d

Cited by 98 publications

(48 citation statements)

References 20 publications

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“…Most recently, we described the first total synthesis of lapidilectine B (38) [23], the first member of this class of Kopsia lapidilecta alkaloids (Scheme 9) [24]. A one-flask imine formation/cycloaddition procedure was effective for the conversion of the carbonyl compound 35 to the cycloadduct 37 in good yield via the stannane 36.…”

Section: Alkaloid Synthesis Via [3+2] Cycloadditions 1343mentioning

confidence: 99%

Alkaloid synthesis via [3+2] cycloadditions

Pearson

2002

Pure and Applied Chemistry

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Tin-lithium exchange on (2-azaallyl)stannanes affords nonstabilized 2-azaallyllithiums (2-azaallyl anions) that undergo [π4s+π2s] cycloadditions with alkenes to afford pyrrolidines. The scope of this method has been expanded to include 2-azapentadienyllithiums and heteroatom-substituted 2-azaallyllithiums. Alternatively, the (2-azaallyl)stannanes may also be used to generate nonstabilized azomethine ylides via N-alkylation/destannylation or N-protonation/destannylation, and these ylides were also found to be useful for the synthesis of pyrrolidines by [π4s+π2s] cycloadditions with alkenes. Applications of both methods to the total synthesis of alkaloids such as (+)-coccinine, lepadiformine stereoisomers, lapidilectine B, and indolizidine 239CD have been accomplished.

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Section: Alkaloid Synthesis Via [3+2] Cycloadditions 1343mentioning

confidence: 99%

Alkaloid synthesis via [3+2] cycloadditions

Pearson

2002

Pure and Applied Chemistry

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“…31b,32 Although these approaches are mostly based in intramolecular reactions, the synthesis of lapidilectine B (Scheme 5, c) is based on a key intermolecular cycloaddition. 39 The smooth reactivity of hetero-substituted olefins was rationalized based on their inductively electron-withdrawing character (and inefficient electron-donation to the π-system of the olefin). 38a This argument is consistent with the inability of heavier analogs to promote the reaction due to insufficient electronegativity.…”

Section: Polyenesmentioning

confidence: 99%

Perspectives on Intermolecular Azomethine Ylide [3+2] Cycloadditions with Non-Electrophilic Olefins

2016

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Our interest in the synthesis of compact nitrogen heterocycles from abundant sources has motivated a critical analysis of the status in azomethine ylide chemistry. Despite the outstanding developments in catalytic enantioselective [3+2] cycloadditions, these are still limited to electron-poor olefins. Only a few examples can be found in the literature that report on cycloadditions using non-electrophilic alkenes and those are compiled herein. With this account we aim to extract lessons and challenges that will inspire future breakthroughs in this area.

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“…Treatment of the major isomer 54 with Eschenmoser's salt followed by removal of the acetonide under acidic conditions yielded the Amaryllidaceae alkaloid (K)-amabiline (55). 31 This methodology using azaallyl organolithiums allowed also the preparation of other natural alkaloids such as (G)-crinine, (G)-6-epicrinine, (K)-augustamine, 31 (G)-lapidectine B, 32a indolizidine 239CD 32b and (C)-coccinine. 32c…”

Section: A-functionalized Sp 3 -Hybridized Organolithiumsmentioning

confidence: 99%