Total synthesis of valeriananoids A, B, and C via autocatalytic diastereoselective domino Michael reaction

Natural sesquiterpenoids

“…385 Valeriananoids A-C have been synthesized via an autocatalytic diastereoselective domino Michael reaction. 386 20 Aromadendrane, bicyclogermacrane, aristolane, nardosinane, lemnane, kelsoane and ishwarane New aromadendrane derivatives 459, 460 and 461 have been found in extracts from Dendrobium nobile, 166 Doellingeria scaber 330 and Erigeron acer, 387 respectively. Another compound of this type 462 has been isolated from the aerial parts of Caragana intermediia.…”

Asymmetric Michael Addition of Unactivated Ketones with β‐Nitrostyrenes Mediated by Bifunctional L‐Prolinamide Organocatalysts

“…Herein, we are reporting our results for the L-prolinamide organocatalyzed Michael reaction. The first reaction was performed between β-nitrostyrene (8 a) and cyclohaxanone (7) at room temperature with 20 mol% catalyst (1) in chloroform. Reaction was completed in 28 h to afford 76% yield of the corresponding product (9 a) with 95 : 5 distereomeric ratio (dr) and moderate enantiomeric excess (ee) of 58% with syn preference ( Table 1, entry 1).…”

“…Michael addition named after Arthur Michael has been known for carbon‐carbon bond formation through conjugate addition of carbanion to α, β‐unsaturated compound in organic synthesis . Resulting Michael adducts serve as key intermediates in total synthesis of various biologically active natural products such as neuropharmacology active (−)‐α‐kainic acid, pregnane steroid hormone Cortisone, antimicrobial compound Claenone, Culmorin, Valeriananoids A, B, and C, (−)‐Epibatidine, Chromenone, Nhatrangin, Armeniaspirol etc . Apart from these, Michael adducts also signify a convenient route for the synthesis of γ‐nitro carbonyl, the nitro group of these carbonyl compounds can further be transformed into an amine, ketone, nitrile oxide, oxime etc…”

Controlling the Facial Selectivity of Asymmetric [4 + 2] Cyclo-additions: A Concise Synthesis of the cis-Decalin Core Structure of Superstolides A and B

“…In addition, the rigid bicyclo[2.2.2]octanone structure can undergo versatile transformations to other molecular structures that are difficult to be constructed . Although a number of methods have been developed for the synthesis of racemic bicyclo[2.2.2]octanone derivatives, asymmetric synthesis of highly functionalized bicyclo[2.2.2]octanone derivatives still poses a formidable synthetic challenge …”