An easy ABD→ABCD strategy to indolo[2,3-a]quinolizin-4-one. Synthesis of deplancheine and yohimbane

Chang, Meng‐Yang; Chen, Chung‐Yi; Chung, Wen‐Sheng; Tasi, Min-Ruei; Chang, Nein-Chen

doi:10.1016/j.tet.2004.11.005

Cited by 10 publications

(1 citation statement)

References 79 publications

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“…The initial synthesis was achieved via formal [3 + 3] cycloaddition reaction of a-sulfonylacetyl tryptamine 239 with an a,b-unsaturated ester, then regioselective reduction of the glutarimide 240, and subsequent dehydration-cyclization of 241 (Scheme 39). 120 In the second, facile and asymmetric approach to both enantiomers of 238 (Scheme 40) the key steps were preparation of indolic bicyclic lactams 242 followed by stereoselective cyclization of the indole nucleus to afford 243. 121 The third total synthesis of This journal is © The Royal Society of Chemistry 2007 A stereocontrolled total synthesis of (−)-eudistomin C 248, obtained from a Caribbean tunicate (Eudistoma olivaceum), 123 has been completed (Scheme 42).…”

Section: B-carbolinesmentioning

confidence: 99%

Simple indole alkaloids and those with a nonrearranged monoterpenoid unit

2007

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Section: B-carbolinesmentioning

confidence: 99%

Simple indole alkaloids and those with a nonrearranged monoterpenoid unit

2007

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Desulfonylation Reactions

Alonso

Ájera

2009

Organic Reactions

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The use of sulfones in organic chemistry, acting as an auxiliary group, is still a very important synthetic strategy, especially for the formation of carbon‐carbon single and double bonds. Once the synthetic objective is achieved, the sulfone gruop is usually removed from the molecule. This removal most commonly involves a reductive desulfonylation process with either replacement of the sulfone by hydrogen, or a process that results in the formation of a carbon‐carbon double bond when a β‐hydroxy or β‐alkoxy sulfone is employed. This chapter is devoted to the replacement of the sulfone group by a hydrogen (reductive desulfonylation reactions), and reductive elimination reactions of Julia‐type substrates (Julia‐Lythgoe olefination process). The chapter addresses the full scope, generality, limitations, and synthetic applications of these reactions. The literature through most of 2007 is covered.

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Diverse Asymmetric Quinolizidine Synthesis: A Stereodivergent One‐Pot Approach

Zhang

Franzén

2010

Adv Synth Catal

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A diverse stereodivergent organocatalytic one-pot addition/cyclization/annulation sequence to optically active quinolizidine derivatives from easily available starting materials is presented. The one-pot sequence relies on a pyrrolidine-catalyzed enantioselective conjugate addition of electron-deficient amide a-carbons to a,b-unsaturated aldehydes, spontaneous hemiaminal formation and acid-catalyzed/ mediated N-acyliminium ion cyclization to give the quinolizidine framework. Simple tuning of the reaction conditions in the N-acyliminuim ion cyclization step provides a diastereomeric switch, which gives access to both of the two bridgehead epimers through kinetic, thermodynamic or chelation control. The methodology display a broad substrate scope that is demonstrated by the stereoselective formation of indolo-, thieno-, benzofuro-, furo-and different benzoquinolizidine derivatives with high atom efficiency, up to > 99% ee and up to > 95:5 dr. Due to its efficiency, synthetic diversity and operational simplicity, this protocol has the potential to find important use as a key step in natural product synthesis, biochemistry and pharmaceutical science. The stereochemical outcome of the one-pot sequence was investigated, and the mechanism and origin of stereoselectivity of the different steps is discussed.

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An easy ABD→ABCD strategy to indolo[2,3-a]quinolizin-4-one. Synthesis of deplancheine and yohimbane

Cited by 10 publications

References 79 publications

Simple indole alkaloids and those with a nonrearranged monoterpenoid unit

Simple indole alkaloids and those with a nonrearranged monoterpenoid unit

Desulfonylation Reactions

Diverse Asymmetric Quinolizidine Synthesis: A Stereodivergent One‐Pot Approach

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