beta-butyltellanyl carbonyl compounds: a useful source of masked metal homoenolates

Abstract

Cianocupratos de ordem superior e homoenolatos de lítio secundários, foram eficientemente gerados a partir de β-butil teluro cetais e submetidos a reação com benzaldeido e 2-cicloexen-1-ona. Secondary higher order cyanocuprates and lithium homoenolates, were efficiently generated from β-butyltellanylketals and reacted with benzaldehyde and 2-cyclohexen-1-one.

A concise enantioselective synthesis of (+)-endo-brevicomin accomplished by a tellurium/metal exchange reaction

“…The resulting organolithium was converted into the higher order cyanocuprate in the usual way, and then reacted with 2. 5,6,9 The hydroxy-ketal originated from this reaction was directly treated with hydrochloric acid or p-TSA resulting in the racemic mixture of (+/-)-(endo/exo)-brevicomin (1) in 70% isolated yield.…”

“…2 Complementary to these methodologies, is the tellurium/ lithium exchange reaction. 3 Previously we demonstrated the synthetic application and efficacy of the tellurium/ lithium exchange reaction to generate functionalized organolithium reagents 4 as well as to prepare other classes of organometallics, including organomagnesium, 5 organocoper, [5][6][7] and organocerium 7 reactive reagents. Herein, we report the enantioselective synthesis of the pine beetle pheromone (+)-endo-brevicomin 8 (1) and its racemic mixture using a telluride as the key precursor of a functionalized organometallic reagent.…”

Terpenoid- and Shikimate-Derived Natural Product Total Synthesis: A Personal Analysis and Commentary on the Importance of the Papers That Appear in this Virtual Issue

“…Importantly, they give us an important insight into why such carbanions form so readily and ultimately get irreversibly protonated (as we see in the conversion of 41 into 42 ); it is because they are stabilized homoenolates that can transiently re-engage the carbonyl (in an anion-stabilizing way) on their passage through to the final products! This synthesis of (−)-marginatafuran has thus very topically brought back, into the limelight, this fascinating aspect of the chemistry of cyclopropanols, and their derived homoenolates, except now we are seeing this chemistry applied in a complex target synthesis setting.…”

Antioxidant effect of functionalized alkyl-organotellurides: a studyin vitro

“…Telluro-ketone A was synthesized by hydrotelluration of methyl vinyl ketone in 86% isolated yield by reacting elemental tellurium with n-butyllithium, followed by the addition of deoxygenated water and the enone as reported previously 25,26 . Tellurides B and C were prepared in good yields according to our previous protocols [27][28][29][30][31] from telluride A.…”