Webb2 nov. 2016 · The first catalytic asymmetric Piancatelli reaction is reported. Catalyzed by a chiral Brønsted acid, the rearrangement of a wide range of furylcarbinols with a series of aniline derivatives provides valuable aminocyclopentenones in high yields as well as excellent enantioselectivities and diastereoselectivities. WebbPiancatelli-type reactions are mechanistic analogous to Nazarov cyclization.8 Although Lewis acids are efficient to accelerate those rearrangements and the following cascade reactions as well,5 the chiral metal complex catalyzed asymmetric version is still void.
The Piancatelli Rearrangement: New Applications for an Intriguing …
WebbAbstract An enantioselective oxa-Piancatelli reaction was established for the first time using a chiral vanadium ( V) catalyst. The dual Brønsted and Lewis acid properties of the vanadium catalyst afforded 4-hydroxycyclopent-2-enone derivatives in up to 90% yields and with 93 : 7 enantiomeric ratios, as well as >20 : 1 diastereomeric ratios. Webb8 okt. 2013 · Since its discovery in 1976, the Piancatelli rearrangement has appeared as a versatile reaction for the construction of substituted cyclopent-2-enones convenient for … dj olomouc
The Piancatelli reaction and its variants: recent …
It was proposed by Piancatelli that the reaction is a thermal electrocyclic reaction of a conrotatory 4π electron system while studying specifics of the mechanism conditions when synthesizing the 4-hydroxycyclopentenone derivatives. Visa mer In 1976, the Italian chemist, Giovanni Piancatelli and coworkers developed a new method to synthesize 4-hydroxycyclopentenone derivatives from 2-furylcarbinols through an acid-catalyzed rearrangement. This … Visa mer The mechanism of this reaction is proposed to be a 4-π electrocyclization very much like the Nazarov cyclization reaction. To obtain the 2-furyl carbinols, Piancatelli subjected furfural, an inedible biomass, to a Grignard reaction. This is then submitted to … Visa mer The harness of the reaction conditions needed for the rearrangement differed based upon the reactivity of the substrates. … Visa mer An important use of the Piancatelli rearrangement that was studied by Piancatelli himself is the synthesis of prostaglandins and their derivatives. Piancatelli was able … Visa mer Webb28 juni 2024 · Abstract Piancatelli rearrangement of furyl carbinols is a relevant reaction to produce cyclopentenone derivatives. However, on a large scale, Piancatelli rearrangement suffers from several... Webb30 sep. 2016 · Abstract A method to extend the scope of the aza-Piancatelli reaction between 2-furylcarbinols and anilines is depicted. We found that 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) is the solvent of choice for this transformation, as it outcompetes the usual solvents in terms of rate and yield. co分子轨道形状