SYNTHESIS OF ALLENE ARYL Δ-Lactones VIA INDIUM-MEDIATED [4+2] CYCLIZATION IN WATER

Hua, Xiao-Gang; Li, Chao‐Jun

doi:10.1515/mgmc.1999.22.9.533

Cited by 3 publications

(1 citation statement)

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“…When methyl 2-(3-bromoprop-1-ynyl)benzoate was subjected to indium-mediated reaction with aldehyde, allenylation followed by an intramolecular cyclization occurred to give allenyl δ-lactone in yields between 51 and 98% (Scheme ) . The reaction worked well with both aromatic and aliphatic aldehydes in aqueous ethanol in the presence of HCl.…”

Section: Propargylindium and Allenylindium Reagentmentioning

confidence: 99%

Organoindium Reagents: The Preparation and Application in Organic Synthesis

et al. 2012

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allylation performed in aqueous media, an efficient synthesis of highly functionalized lactones was realized in good yields (64− 77%, Scheme 29). 238 However, the chirality installed during the first step almost had no influence on the second step, thus resulting in poor diastereoselectivity in the subsequent allylation reaction (1:1−2:1 dr).In situ formation of aldehyde from the oxidation of alcohol followed by one-pot indium-mediated allylation also provides an alternative method for the synthesis of homoallylic alcohol. Recently, Yadav and co-workers developed such a one-pot sequence by using chloramines-T (sodium salt of Nchlorotosylamide) as oxidant in the presence of a catalytic amount of FeCl 3 in CH 2 Cl 2 , giving rise to homoallylic alcohols in good to excellent yields (Scheme 30). 239 It is noteworthy that the generated byproduct of TsNH 2 (from the reduction of chloramines-T) may react with the in situ-formed aldehydes to give intermediates of N-tosylimines in the presence of 4 Å molecular sieve under refluxing; the thus-formed N-tosylimines subsequently underwent one-pot indium-mediated allylation to produce homoallylic amines in 60−80% yields. Later, a similar one-pot, two-step sequence for the synthesis of homoallylic alcohols via a galactose oxidase-mediated chemo-enzymatic oxidation of benzyl and cinnamyl alcohols to the corresponding Scheme 23 Scheme 24 Scheme 25 Scheme 26 Scheme 27 Scheme 28 Scheme 29 Scheme 30 Chemical Reviews Review dx.

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Section: Propargylindium and Allenylindium Reagentmentioning

confidence: 99%