Asymmetric Michael Addition of N-tert-Butanesulfinyl Imidate with α,β-Unsaturated Diesters: Scope and Application to the Synthesis of Indanone Derivatives

Abstract

An additive-free and highly diastereoselective Michael addition reaction of an N-tert-butanesulfinyl imidate to α,β-unsaturated diesters has been developed using LDA as a base with good to excellent yields. The utility of this chemistry is further demonstrated by the asymmetric synthesis of 3-substituted indanone derivatives 8a, 8d, 8e, and 8i with high enantiomeric excess, which are potential building blocks for preparing biologically active lead compounds.

Transformations of Conjugated Enynones in the Superacid CF3SO3H. Synthesis of Butadienyl Triflates, Indanones, and Indenes

“…It should be noted that vinyl triflates are in great demand for organic synthesis of cross-couplings and other reactions. ,− Concerning indanones, much effort is given to their synthesis − due to the biological activity of these compounds. , …”

Total Syntheses of (−)‐Isoschizogamine and (−)‐2‐Hydroxyisoschizogamine

“…The retrosynthetic analysis of (À)-isoschizogamine (1)a nd (À)-2-hydroxyschizogamine (15)i ss hown in Scheme1.W e envisioned that the amide bond in isoschizogamine (1) Based on the retrosynthetic analysis, we began the total synthesis by preparing the intermediate 20 with C, D, and Er ings (Scheme 2). Our group and Liu'sg roup [13,14] have reported that chiral N-tert-butanesulfinyl imidate-induced [15] Michael addition to a,b-unsaturatede ster usually provides adducts with excellent yields and diastereoselectivities. The addition reaction of imidate (R)-24 with diester 25 afforded two separabled iastereomers 26 a and 26 b in a5 :1 ratio in 90 %c ombined yield.…”

Asymmetric Conjugate Addition of Malonate Esters to α,β‐Unsaturated N‐Sulfonyl Imines: An Expeditious Route to Chiral δ‐Aminoesters and Piperidones

“…Both diastereomers 5 and 6 could be separated after column chromatography and subjected to chemical transformations separately. Decarboxylation of either 5 or 6 upon treatment with tetraethylammonium hydroxide20 in DMSO gave the monoesters 7 and 8 in 70 and 60 % yield, respectively. Finally, we carried out the lactamization of compounds 5 and 7 to give the chiral piperidones 9 21 and 10 , respectively, by basic treatment with lithium hexamethyl disilazide (LiHMDS) in toluene 22…”