Expeditious Divergent Synthetic Approach to Polycyclic Terpene‐Like Molecules

Bifunctional nickel precatalysts of amido-functionalized N-heterocyclic carbenes for base-free Michael reaction under ambient conditions

“…It is thus anticipated that the absence of a base would suppress all of the undesired secondary reactions that unfavorably affects the reaction yield. In this regard two different strategies have been employed in achieving base-free Michael addition, the one taking recourse to organocatalysis [18] while the other employing transition metals [19e21]. A common premise that runs beneath both these approaches involves the use of bifunctional catalysts possessing both acidic and basic sites [22e25].…”

Time‐Efficient Synthesis of Pyrido­[2,3‐d]pyrimidinones via α‐Oxoket­enes

“…[7] Using this approach, the chemistry of these electrophilic reactive intermediates has been revisited, including their reactions with heteroatom-based, [8] carbon-based, [9] and silylated nucleophiles, [10] N,N-bis-nucleophiles, [11] imines, [12] 1,3-dipoles, [13] and aza-dienes. [7] Using this approach, the chemistry of these electrophilic reactive intermediates has been revisited, including their reactions with heteroatom-based, [8] carbon-based, [9] and silylated nucleophiles, [10] N,N-bis-nucleophiles, [11] imines, [12] 1,3-dipoles, [13] and aza-dienes.…”

Cross-Metathesis/Intramolecular (Hetero-)Michael Addition: A Convenient Sequence for the Generation of Carbo- and Heterocycles

“…Scheme 31 Scope of the CM/Michael spirocyclization sequence When this synthetic strategy was extended to enals as the CM partners, a cascade involving Wolff rearrangement/ CM/IMMR/intramolecular aldol reaction was triggered in a consecutive manner, giving rise to the formation of tricyclo[7.2.1.0]dodecane ring systems, which are scaffolds present in several classes of terpenoids. 51 Thermally induced Wolff rearrangement of 2-diazo-1,3-cyclohexanedione 71a in the presence of allylbenzylamine ended with the trapping of the acyl ketene intermediate to render the ring-contracted β-keto amide 72a. Acrolein and second-generation Hoveyda-Grubbs complex I were immediately added to the reaction vessel and it was heated again under microwave irradiation to furnish enal 73a.…”