Highly efficient synthesis of tri- and tetrasubstituted conjugated enynes from Brønsted acid catalyzed alkoxylation of 1-cyclopropylprop-2-yn-1-ols with alcohols.

doi:10.1021/jo9008244

Paper

Highly efficient synthesis of tri- and tetrasubstituted conjugated enynes from Brønsted acid catalyzed alkoxylation of 1-cyclopropylprop-2-yn-1-ols with alcohols.

Published Jul 24, 2009 · S. R. Mothe, P. Chan

The Journal of organic chemistry

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30

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Abstract

A highly efficient triflic acid catalyzed ring opening of a wide variety of 1-cyclopropyl-2-propyn-1-ols with alcohols as an efficient synthetic route to conjugated enynes is reported herein. The reaction was operationally straightforward and accomplished in good to excellent yields (44-100%), high product turnovers (up to 10,000), and with complete regioselectivity under mild conditions with a low catalyst loading of 0.01 mol %. The mechanism is suggested to involve protonation of the alcohol substrate by the TfOH catalyst, followed by ionization of the starting material. This causes ring opening of the cyclopropane moiety and trapping by the alcohol nucleophile to give the conjugated enyne product. The synthetic utility of the present method was also exemplified by the efficient large-scale conversion in gram quantities of one example studied in this work to the corresponding conjugated enyne product in excellent yield and turnover number.

Study Snapshot

This study presents a highly efficient, mild, and regioselective method for the synthesis of tri- and tetrasubstituted conjugated enynes from 1-cyclopropylprop-2-yn-1-ols with alcohols, achieving high yields and product

PopulationOlder adults (50-71 years)

Sample size24

MethodsObservational

OutcomesBody Mass Index projections

ResultsSocial networks mitigate obesity in older groups.

Paper

Highly efficient synthesis of tri- and tetrasubstituted conjugated enynes from Brønsted acid catalyzed alkoxylation of 1-cyclopropylprop-2-yn-1-ols with alcohols.

References

Citations

Recent Advancements in Metal‐Free Catalysis for Cyclopropane Ring Cleavage

Recent advances in metal-free catalysis for cyclopropane ring cleavage have led to improved reactions using various acids, bases, and ionic liquids.

Acid‐Catalyzed Ring Opening Reaction of Cyclopropyl Carbinols with Acetonitrile to Synthesize Amides

A one-pot protocol using acetonitrile as nitrogen source and solvent effectively synthesizes amides from cyclopropyl carbinols, yielding moderate to good yields.

Rapid Access to Arylated and Allylated Cyclopropanes via Brønsted Acid-Catalyzed Dehydrative Coupling of Cyclopropylcarbinols.

This study presents a rapid, regioselective method for the synthesis of cyclopropyl derivatives using Brookhart acid-catalyzed dehydrative coupling, offering excellent yields and utility with various cyclopropylcarbinols.

CuBr2-catalyzed ring opening/formylation reaction of cyclopropyl carbinols with DMF to synthesize formate esters

This study developed a novel method for synthesizing formate esters using cyclopropyl carbinols and DMF, resulting in moderate to good yields and smooth participation of different substrate groups.

Rh(II)/Ag(I) co-catalyzed three-component reaction via SN1/SN1'-type trapping of oxonium ylide with Nicholas intermediate.

This Rh(II)/Ag(I) co-catalyzed three-component reaction efficiently constructs dicobalt-hexacarbonyl-complexed 3,3-disubstituted oxindoles with ene alkynyl group and