TY - JOUR
T1 - Gold-Catalyzed Bicyclic and [3+2]-Annulations of Internal Propargyl Alcohols with Nitrones and Imines To Yield to Two Distinct Heterocycles
AU - More, Sayaji Arjun
AU - Chao, Tzu Hsuan
AU - Cheng, Mu Jeng
AU - Liu, Rai Shung
N1 - Funding Information:
We thank the Ministry of Education (MOE 106 N506CE1) and the Ministry of Science and Technology (MOST 107‐3017‐F‐007‐002), Taiwan, for financial support of this work.
Publisher Copyright:
© 2020 Wiley-VCH GmbH
PY - 2021/1/19
Y1 - 2021/1/19
N2 - A gold-catalyzed synthesis of 1,3-dihydrooxazolo[3,4-a]indoles from 1-oxo-3-yn-4-ols and nitrones is described; this new bicyclic annulation presents the first examples that internal alkynes can react with nitrones to undergo an oxoarylation route. DFT calculations indicate a [3,3]-sigmatropic shift of initial alkenylgold intermediates to elude the intermediacy of gold carbenes. We also developed new [3+2]-annulations of the same 1-oxo-3-yn-4-ols with imines, yielding oxazolidin-4-ylidene derivatives efficiently. The tethered alcohols of these 1-oxo-3-ynes allow trapping of their metastable 2-azadienium intermediates to enable a novel annulation. Our mechanistic analysis indicates that the two products, despite their structural relevance, are produced from two independent systems. (Figure presented.).
AB - A gold-catalyzed synthesis of 1,3-dihydrooxazolo[3,4-a]indoles from 1-oxo-3-yn-4-ols and nitrones is described; this new bicyclic annulation presents the first examples that internal alkynes can react with nitrones to undergo an oxoarylation route. DFT calculations indicate a [3,3]-sigmatropic shift of initial alkenylgold intermediates to elude the intermediacy of gold carbenes. We also developed new [3+2]-annulations of the same 1-oxo-3-yn-4-ols with imines, yielding oxazolidin-4-ylidene derivatives efficiently. The tethered alcohols of these 1-oxo-3-ynes allow trapping of their metastable 2-azadienium intermediates to enable a novel annulation. Our mechanistic analysis indicates that the two products, despite their structural relevance, are produced from two independent systems. (Figure presented.).
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U2 - 10.1002/adsc.202001119
DO - 10.1002/adsc.202001119
M3 - Article
AN - SCOPUS:85096771809
VL - 363
SP - 525
EP - 531
JO - Advanced Synthesis and Catalysis
JF - Advanced Synthesis and Catalysis
SN - 1615-4150
IS - 2
ER -