Microwave‐assisted synthesis and diels–alder reactions of 1,3‐azaphospholo[5,1‐<i>a</i>]isoquinolines

Bansal, R. K.; Dandia, Anshu; Gupta, Nishi; Jain, Divya

doi:10.1002/hc.10193

Cited by 15 publications

(7 citation statements)

References 28 publications

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“…24 The DA reaction of 17 (R 1 R 2 = -CH=CH-CH=CH-, R 3 = H) could be accomplished more rapidly under microwave irradiation without affecting the yields or the stereo-and regioselectivities. 25 The observed stereo-and regioselectivities in the above reactions could be rationalized on the basis of density functional theory (DFT) calculations. 26 Scheme 5…”

Section: Diels-alder Reactions Of 13-azaphospholo[15-a]pyridines Imentioning

confidence: 99%

Diels–Alder Reactions with the >C=P– Functionality of Annelated Azaphospholes

Bansal

Kour

2015

Synlett

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The >C=P-functionality in annelated azaphospholes acts as a dienophile and undergoes Diels-Alder reactions with dienes. 1,3-Bis(alkoxycarbonyl)-2-phosphaindolizines react with dienes even in the absence of a catalyst; however, in the presence of an oxidizing agent such as sulfur or selenium, the reaction is much faster. 3-Alkoxycarbonyl-2-phosphaindolizines with an electron-withdrawing group exclusively at position 3 undergo the Diels-Alder reaction only in the presence of a Lewis acid. Density functional theory calculations reveal strong hyperconjugative interactions between the nitrogen lone pair and the >C=P-functionality of the 3-alkoxycarbonyl-2-phosphaindolizine, making it electron-rich. However, in 1,3-bis(alkoxycarbonyl)-2-phosphaindolizines, the ester group at the position 1 acts as a sink for the lone pair of electrons of nitrogen leaving the >C=P-functionality sufficiently electron-deficient to undergo the Diels-Alder reaction.

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Section: Diels-alder Reactions Of 13-azaphospholo[15-a]pyridines Imentioning

confidence: 99%

Diels–Alder Reactions with the >C=P– Functionality of Annelated Azaphospholes

Bansal

Kour

2015

Synlett

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“…The ❍ ❍ ✟ ✟C P moiety in the heterophospholes, as in acyclic phosphaalkenes [26][27][28][29], acts as dienophile and undergoes [2 + 4] cycloaddition with a variety of 1,3-dienes, such as 2,3-dimethylbutadiene, 1,4-diphenylbutadiene, isoprene, cyclopentadiene, 1,4-diphenylazabutadiene and o-quinones [13,[30][31][32][33][34][35][36][37][38][39]. The reaction with unsymmetrical diene such as isoprene or 1,4-diphenylazabutadiene proceeds regioselectively, the regioselectivity in many cases being 100%.…”

Section: [2 + 4] Cycloadditionsmentioning

confidence: 99%

Cycloaddition reactions of heterophospholes

Bansal

Gupta

2004

Heteroatom Chemistry

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“…The extent of regioselectivity in the reaction with isoprene, however, depends on the nature of the oxidizing agent, in the presence of sulfur it is 100%, whereas in the presence of methyl iodide it decreases to 62% [14]. These reactions could be accomplished under microwave irradiation in much shorter time without affecting the stereoand regioselectivities [15]. The DA reactions of thiazolo [3,2-d][1,4,2]diazaphospholes and their 5,6-dihydro-and benzo-derivatives and those of 1,3-azaphospholo [5,1-b]benzothiazole occur with complete endo stereoselectivity, and in the reaction with isoprene, 70-100% regioselectivity is observed [16].…”

Section: Introductionmentioning

confidence: 89%