Propargylic acetals rearrangement

It is worth noting that a silyl group at the propargyl position did not interfere with the silver-catalyzed rearrangement of a propargyl acetate, despite the potential for further evolution of the product (Scheme 3.34).55... 

RXN59 Preparation of a-Diketones Derivatives via an Oxidative Rearrangement of a Propargyl Acetate... 

Representative procedure for the gold-catalyzed Meyer-Schuster-rearrangement of propargyl acetates. (E)-l-Phenyloct-2-en-4-on ... 

Representative procedure for the gold-catalyzed rearrangement of aromatic propargyl acetates to indenes. 5-Butyl-5H-indeno[5,6-d][l,3]dioxol-5-yl acetate... 

A gold(I)-catalysed homo-Rautenstrauch rearrangement of 1-cyclopropyl propar-gylic esters to cyclohexenones is considered evidence for the gold-stabiUzed nonclassical carbocation character of intermediates. A mechanistic study revealed 0 partial chirality transfer from optically active propargyl acetates (Scheme 125). 

Other rearrangements in this class include the allylacetylene-vinylallene isomerization with various substituent groups the reaction of methyl-magnesium iodide and magnesium iodide with propargyl acetates the... 

Fiirstner, A., Hannen, P. (2006). Platinum- and gold-catalyzed rearrangement reactions of propargyl acetates total syntheses of (—)-alpha-cubebene, (—)-cubebol, sesquicarene and related terpenes. Chemistry - A European Journal, 12, 3006-3019. 

Scheme 2.19 Au-catalysed cycloisomerisation/rearrangements of propargylic acetates.

Synthesis of Hydroxy-acids.— The allylborane (15) (Scheme 10) is readily obtained from an optically active propargyl acetate by hydroboration and rearrangement (with sodium hydroxide). Its reaction with an aldehyde then gives (16) in 63% yield and 80% enantiomeric excess subsequent ozonolysis and oxidation then... 

The reaction of lithium diisopropylamide with propargyl acetate 3.559 followed by treatment of the enolate formed with trimethylchlorosilane at —78°C affords ketene acetal 3.561. After heating the reaction mixture to 40°C, the intermediate vinylpropargyl ether 3.560 undergoes the Claisen rearrangement to produce silyl ester 3.561, which after hydrolysis forms allenyl-acetic acid 3.562 with a 50% overall yield (Scheme 3.42) [281]. This reaction is of interest as a synthetic strategy for obtaining the benzoannelated enyne-allene that by radical cyclization forms polycyclic aromatic compounds with an embedded fluorene section [281]. (Scheme 3.43)... 

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