Molybdenum(V) chloride-catalyzed amidation of secondary benzyl alcohols with sulfonamides and carbamates

Reddy, Chada Raji; Madhavi, P. Phani; Reddy, A. Syamprasad

doi:10.1016/j.tetlet.2007.07.204

Cited by 69 publications

(19 citation statements)

References 31 publications

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“…At a lower temperature, methylfuran reacted with allylic and benzylic alcohols. [115] The use of MoCl 5 in the reaction of benzylic alcohols with amides was reported by Reddy, [116] and the same author reported the use of MoCl 5 in other C-C bond-forming reactions. [117] NbCl 5 , a stable solid, which is easy to handle and soluble in many organic solvents, has also been well explored as a Lewis acid in promoting various organic transformations; [118] it was used in the nucleophilic addiction of C, N, O, and S nucleophiles to benzylic alcohols 1 and 2.…”

Section: Molybdenum and Niobium Lewis Acids Complexesmentioning

confidence: 91%

Direct Nucleophilic S_N1‐Type Reactions of Alcohols

et al. 2010

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In 2005, the ACS Green Chemistry Institute (GCI) and the global pharmaceutical corporations developed the ACS GCI Pharmaceutical Roundtable to encourage the development of green chemistry and green engineering in the pharmaceutical industry. The Roundtable has established a list of key research areas including the direct nucleophilic reactions of alcohols. The substitution of activated alcohols is a frequently used approach for the preparation of active pharmaceutical ingredients. Alcohols are transformed into the reactive halides or sulfonate esters, thereby allowing their reaction with nucleophiles. Although the direct nucleophilic substitution of an alcohol should be an attractive process, as one of the byproducts from the reaction yields water, hydroxide is a poor leaving group that hinders the reaction. Recently, the direct substitution of allylic, benzylic, and tertiary alcohols has been achieved through an SN1 reaction with catalytic amounts of Brønsted or Lewis acids. In this review, the approaches leading to a greener process are examined in detail, and the advances achieved to date in this important transformation are presented.

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Section: Molybdenum and Niobium Lewis Acids Complexesmentioning

confidence: 91%

Direct Nucleophilic S_N1‐Type Reactions of Alcohols

et al. 2010

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“…Although a number of direct aminations of alcohols catalyzed by transition metals have been reported, the use of a primary amide with weak nitrogen nucleophiles is uncommon and requires harsh conditions . Recently, a few Lewis acid and Brønsted acid catalyzed aminations of alcohols with primary amides have been described, including those of FeCl 3 , MoCl 5 , triflate salts, I 2 , phosphotungstic acid, and HClO 4 /SiO 2 . However, these methods have disadvantage(s) such as a requirement for toxic or expensive metal reagents, drastic reaction conditions, unsatisfactory yields and poor recyclability of catalysts.…”

Section: Resultsmentioning

confidence: 99%

Air‐stable Bis(pentamethylcyclopentadienyl) Zirconium Perfluorooctanesulfonate as an Efficient and Recyclable Catalyst for the Synthesis of N‐substituted Amides

et al. 2018

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Bis(pentamethylcyclopentadienyl) zirconium perfluorooctanesulfonate is an air-stable and water-tolerant Lewis acid. This complex exhibited good thermal stability and high solubility in polar organic solvents. The compound showed relatively strong acidity, with an acid strength of 0.8 < Ho 3.3, and high catalytic efficiency for the synthesis of N-substituted amides via the reaction of carboxylic acids with amines, the Ritter reaction of nitriles with alcohols, and the amination of alcohols with amides. Moreover, the complex had good reusability. This catalytic system affords a simple and efficient way to synthesize N-substituted amides.

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“…Benzyl N ‐(1,3‐Diphenyl‐2‐propynyl)carbamate (7be): 16 R f = 0.40 (hexane/ethyl acetate = 3:1). 1 H NMR (300 MHz, CDCl 3 ): δ = 5.13 (br., 2 H), 5.42 (br., 1 H), 5.95 (br., 1 H), 7.22–7.40 (m, 11 H), 7.40–7.50 (m, 2 H), 7.50–7.60 (m, 2 H) ppm.…”

Section: Methodsmentioning

confidence: 99%

SnCl₂‐Catalyzed Propargylic Substitution of Propargylic Alcohols with Carbon and Nitrogen Nucleophiles

2013

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A weak Lewis acid, tin(II) chloride, which is insensitive to water and air, functioned as a catalyst for the propargylic substitution of secondary propargylic alcohols with carbon nucleophiles, such as electron‐rich arenes, heteroarenes, and 1,3‐dicarbonyl compounds, and nitrogen nucleophiles, such as sulfonamides, carbamates, and carboxamides, at 40–80 °C in CH3NO2 under air and exhibited a higher catalytic activity than tin(II) bromide or iodide in the propargylic substitution of 1‐phenyl‐2‐propyn‐1‐ol with anisole at 40 °C in CH3NO2. The solubility of tin(II) fluoride in CH3NO2 would have to be extremely low to cause no propargylic substitution. 1‐Phenyl‐substituted propargylic alcohols readily reacted with all these nucleophiles, whereas 1‐(4‐cyanophenyl)‐2‐propyn‐1‐ol and 1‐(pentafluorophenyl)‐2‐propyn‐1‐ol did not react at all with 1,2,3‐trimethoxybenzene even in CH3NO2 at reflux. The 1‐alkyl‐substituted secondary propargylic alcohol, 1,5‐diphenyl‐1‐pentyn‐3‐ol, underwent SnCl2‐catalyzed propargylic substitution with electron‐rich arenes and amides, although the reaction was slow even at 80 °C in CH3NO2. Thus, the SnCl2‐catalyzed propargylic substitution reaction is dependent upon the stability of the propargylic carbenium ion formed upon elimination of hydroxide from the corresponding propargylic alcohol.

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Molybdenum(V) chloride-catalyzed amidation of secondary benzyl alcohols with sulfonamides and carbamates

Cited by 69 publications

References 31 publications

Direct Nucleophilic S_N1‐Type Reactions of Alcohols

Direct Nucleophilic S_N1‐Type Reactions of Alcohols

Air‐stable Bis(pentamethylcyclopentadienyl) Zirconium Perfluorooctanesulfonate as an Efficient and Recyclable Catalyst for the Synthesis of N‐substituted Amides

SnCl₂‐Catalyzed Propargylic Substitution of Propargylic Alcohols with Carbon and Nitrogen Nucleophiles

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Molybdenum(V) chloride-catalyzed amidation of secondary benzyl alcohols with sulfonamides and carbamates

Cited by 69 publications

References 31 publications

Direct Nucleophilic SN1‐Type Reactions of Alcohols

Direct Nucleophilic SN1‐Type Reactions of Alcohols

Air‐stable Bis(pentamethylcyclopentadienyl) Zirconium Perfluorooctanesulfonate as an Efficient and Recyclable Catalyst for the Synthesis of N‐substituted Amides

SnCl2‐Catalyzed Propargylic Substitution of Propargylic Alcohols with Carbon and Nitrogen Nucleophiles

Contact Info

Product

Resources

About

Direct Nucleophilic S_N1‐Type Reactions of Alcohols

Direct Nucleophilic S_N1‐Type Reactions of Alcohols

SnCl₂‐Catalyzed Propargylic Substitution of Propargylic Alcohols with Carbon and Nitrogen Nucleophiles