An enantioselective approach to ring a of taxol using the wieland-miescher ketone

The Wieland-Miescher Ketone: A Journey from Organocatalysis to Natural Product Synthesis

“…7n, 129 The WMK was also used as a starting point for the western fragment (A ring) of taxol 148 by the group of Watt. 130 The angular methyl group served to induce a diastereoselective attack of cyanide leading to 146 with the desired tertiary alcohol stereochemistry. Oxidative ring opening to 147, followed by decarboxylation with Wilkinson's catalyst, formed the gem-dimethyl group of taxol.…”

Efficient and selective catalytic oxidative cleavage of α-hydroxy ketones using vanadium-based HPA and dioxygen

“…In many synthetic schemes, including that of Taxol ® , ring opening strategies are based on prior formation of a-hydroxy ketones. 4 Most of the published procedures use stoichiometric reagents. 5 Efforts have been made to find dioxygen-based catalytic pathways running either with Bi(0)/Bi(III) salts or moisture-sensitive dichloro(ethoxy)oxy vanadium complexes.…”

Recent progress in the synthesis of taxanes

“…The Wieland-Miescher ketone 266 has also been used in an A-ring synthesis (Scheme 42). 75 Protection of the a,#?-unsaturated carbonyl group in 266 with 1,2ethanedithiol gave a thioacetal and, despite the fact that the saturated carbonyl group is hindered, addition of t-butyldimethylsilyl cyanide proceeded stereoselectively to produce the protected cyanohydrin 284. Selective removal of the thioacetal group in 284 occurred with Tl(NO,), leading to the enone 285.…”