General approach for the synthesis of polyquinanes. Facile generation of molecular complexity via reaction of 1,2-dicarbonyl compounds with dimethyl 3-

Cycloadditions of allylsilances. Part 10. Stereoselective Construction of Ring Systems by Cycloaddition Reactions of allyltriisopropylsilance

“…Domino reactions offer the possibility for multiple bond formations and thus, the construction of polycyclic ring systems in a one-pot reaction [16]. The Weiss reaction represents an example for such a process, where in a sequence of aldol and Michael reactions the bicyclo[3.3.0]octane framework is furnished by the generation of four carbon-carbon bonds starting from one central C2-unit (glyoxal) and two C3-moieties (dimethyl 3oxoglutarate) [17]. We devised a novel one-pot construction of the bicyclo Methyl vinyl ketone 6 as an example of an acyclic enone provided under the same optimized reaction conditions almost quantitatively the cyclopentane 7 with a 1O:l ratio in favor of the anti diastereoisomer (Scheme 4) [13].…”

Synthetic Approaches to Natural and Unnatural Tetraquinanes

“…In 1985, Cook and co‐workers extended their previously developed strategy [16a] to construct the fenestrane‐based tetraquinane system 124 using diborane mediated reduction as a key step. Diketo diacid 122 is synthesized from benzyl acetoacetate 121 via a 8‐step reaction sequence, which gets transformed into tetracyclic derivative 123 .…”

Cycloadditions of Allylsilanes - Part 22.¹ Stereoselective Synthesis of Cyclopentanes and Cyclobutanes by Lewis Acid Promoted [3+2] and [2+2] Cycloadditions of Allylsilanes

“…70,71 The Cook-Weiss reaction (addition of dimethyl acetonedicarboxylate to glyoxal) represents such a process for the synthesis of bicyclo [3.3.0]octanes and involves a one-pot annulation of two five-membered rings at a central C 2building block. [72][73][74] We described an alternative one-pot construction of the bicyclo[3.3.0]octane framework by a domino [3+2] cycloaddition of allyltriisopropylsilane (1i) and butynone (11) (Scheme 5). 75 The reaction of one equivalent of allylsilane 1i with the titanium tetrachloride complex of butynone (11)…”