71009-11-5Relevant articles and documents
Operationally simple and efficient workup procedure for TBAF-mediated desilylation: Application to halichondrin synthesis
Kaburagi, Yosuke,Kishi, Yoshito
, p. 723 - 726 (2007/10/03)
An operationally simple and efficient workup method for tetrabutylammonium fluoride (TBAF)-mediated t-butyldimethylsilyl (TBS) deprotection has been developed. The procedure includes addition of a sulfonic acid resin and calcium carbonate, followed by filtration and evaporation. This method eliminates the tedious aqueous-phase extraction process to remove excess TBAF and materials derived from TBAF, thereby making the protocol highly amenable to multiple TBS deprotections. Its efficiency and usefulness were demonstrated by using the transformation of 1 a to 3a in the halichondrin synthesis.
Acid-catalyzed solvolysis of polyenol ethers. III. Effect of the alkoxy moiety
Nieuwenhuis, Saskia A. M.,Vertegaal, Louis B. J.,De Zoete, Marian C.,Van Der Gen, Arne
, p. 13207 - 13230 (2007/10/02)
The dependence of the solvolysis of polyenol ethers on the nature of the alkoxy moiety has been studied. A new reaction path, leading to the formation of ω-hydroxy (methoxy) substituted aldehydes and -esters, was established. The proposed reaction pathway (scheme 6) is initiated by an electron transfer from the polyenol ether to molecular oxygen, followed by combination of the two radicals to a peroxide zwitterion. Upon protonation, solvent adds to the ω-carbon atom of the polyene to give an intermediate that can either loose water to form an ester, or loose the alkoxy moiety to give an aldehyde. This mechanism is believed to be involved in the strong mutagenic activity displayed by many polyenol ethers, including the natural mutagen fecapentaene-12.
