27644-06-0Relevant articles and documents
Forging C-C Bonds with Hindered Nucleophiles and Carbonyl Electrophiles: Reactivity and Selectivity of Allylic Tin Reagents/n-BuLi
Cormier, Morgan,Ahmad, Maha,Maddaluno, Jacques,De Paolis, Micha?l
, p. 4920 - 4927 (2018/02/07)
Under activation with n-BuLi, trialkylstannanes containing crotyl-, geranyl-, and phenyldienylmethyl appendages were reacted with efficiency and selectivity to various ketone and enone electrophiles with low reactivity. The straightforward process gives access to tertiary alcohols that are vicinal to quaternary carbons. With α,α′-dimethoxy-γ-pyrone, on the other hand, the grafting of a dienyl side chain was effected to prepare dienyl α′-methoxy-γ-pyrone in a stereo- and regioselective and convergent manner. Furthermore, the advantages of this route were highlighted for the preparation of organolithium species at low temperature with the formation of a minimum amount of salts. Synthetic manipulations were demonstrated to illustrate the potential of the chemistry for constructing acyclic and cyclic terpene scaffolds.
Dibutyltin oxide catalyzed allyl-transfer reaction from tertiary homoallylic alcohols to aldehydes
Yanagisawa, Akira,Aoki, Takahiro,Arai, Takayoshi
, p. 2071 - 2074 (2008/02/05)
A catalytic allyl-transfer reaction from tertiary homoallylic alcohols to aldehydes was achieved using dibutyltin oxide as a catalyst in toluene under reflux conditions. Various secondary homoallylic alcohols were prepared in high yield (up to 99%). When β-alkylated tertiary homoallylic alcohols were used, branched products were exclusively obtained. Georg Thieme Verlag Stuttgart.
In situ formation of allyl ketones via Hiyama-Nozaki reactions followed by a chromium-mediated Oppenauer oxidation
Schrekker, Henri S.,De Bolster, Martin W. G.,Orru, Romano V. A.,Wessjohann, Ludger A.
, p. 1975 - 1981 (2007/10/03)
In Hiyama-Nozaki reactions of allylchromium with aldehydes the expected products are homo-allylalcohols. However, oxidation products derived from these, predominantly allyl ketones, can be common side products. This can be explained by an Oppenauer-(Meerwein-Ponndorf-Verley)-type mechanism (OMPV-reaction). The amount of oxidation is strongly dependent on the substitution pattern of the reaction partners and the reaction conditions. An appropriate choice of these can lead to preferential formation of ketones instead of the alcohols. In addition to its synthetic usefulness, the oxidation-reduction equilibrium is of the utmost importance for the design of enantioselective Hiyama-Nozaki reactions because it is also a potential racemization pathway.