Annulative Morita–Baylis–Hillman reaction to synthesise chiral dibenzocycloheptanes

Abstract

We describe the first metal-free and organocatalytic strategy to access highly functionalised dibenzocycloheptanes via phosphine-promoted annulative Morita-Baylis-Hillman (MBH) reaction. The method is manipulated to access to chiral dibenzocycloheptanes as well....

Synthesis of Bridged N,O‐Heterocyclic 1,6‐Epoxybenzo[c]azocines via Migration‐Annulation Cascade Reaction of α‐Imino Rhodium Carbenes

“…Therefore, the reaction time had to be shortened. The most effective dosage of rhodium catalyst was proved to be 2 mol% (entries [16][17] and the most efficient concentration was 0.1 M (entries [18][19]. Therefore, the optimized reaction conditions for the generation of 7 a were established as indicated in entry 14.…”

“…Additional references cited within the Supporting Information. [16][17][18][19][20][21][22][23][24] The Supporting Information contains general information, procedures, data and NMR spectra and X-ray data.…”

Conceptual advances in nucleophilic organophosphine-promoted transformations

“…Continuing our journey in IMBH chemistry, we realised that biaryl enone-aldehydes 14 can be suitable substrates to synthesise dibenzocycloheptanes 15 , Scheme 6. 22 The dibenzocycloheptane moiety is an important core in various bioactive natural products and pharmaceutically relevant compounds, crucial in several drug discovery programs. 23 In this context, various synthetic methods are known to construct dibenzo-fused cycloheptanones.…”

Catalytic asymmetric synthesis of medium-sized bridged biaryls

“…In 2021, Ramasastry's group achieved the asymmetric synthesis of dibenzocycloheptanones via chiral phosphine C-5 -catalysed annulative Morita–Baylis–Hillman (MBH) reaction of enone-aldehydes 67 (Scheme 17). 36 Only 3-examples have been probed to achieve poor yields, and moderate enantio - and diastereoselectivities of the products 68 . Alternatively, employing enantiopure axially chiral enone-aldehydes in the presence of an achiral phosphine catalyst, the MBH reaction takes place without losing the enantioselectivity to provide the desired products in acceptable to good diastereoselectivities.…”