The first total synthesis of dinemasone A, a bioactive metabolite with a spiroketal moiety, is described. The main strategy for the construction of the spiroketal unit involves a double intramolecular hetero-Michael addition (DIHMA) of an ynone moiety. The thus obtained axial-equatorial mono anomeric spiroketal, on spiroepimerization with ZnBr(2), was converted into the requisite axial-axial do...

A highly enantioselective intramolecular 6-exo-trig aza-Michael addition was developed to afford chiral 3-substituted 1,2-oxazinanes in high yields (up to 99% yield) and good enantioselectivities (up to 98/2 er). These reactions were enabled by a quinine-derived primary-tertiary diamine as a catalyst and pentafluoropropionic acid (PFP) as a co-catalyst.

An activated Michael acceptor type of probe by an intramolecular hydrogen bond has shown a selective fluorescence turn-on response to cyanide through a conjugated addition of the nucleophilic anion to the enone probe with a 1300-fold increase in its fluorescence intensity.

It has been revealed for the first time that co-promoted by CuCl and NaH in the presence of molecular oxygen (air), the reaction of dicinnamoyl ketene dithioacetals as the acyclic C6 synthons with ethyl cyanoacetate gives functionalized seven-membered carbocycles. A mechanism is proposed involving a tandem Michael addition-intramolecular radical cyclization-benzyl C(sp(3))-H bond oxidation.

A novel and efficient method for the construction of γ-lactams with an all-carbon quaternary center is developed via a DABCO-catalyzed reaction of EWG-activated cyclopropanecarboxamides and electron-deficient alkenes. The process involves sequential ring-opening of activated cyclopropanes, intermolecular Michael addition and intramolecular aza-cyclization.

A stereocontrolled strategy toward the synthesis of nagelamide K has been developed. The dimeric imidazole acrylate, diimidazolidenesuccinate, was constructed as a synthetic precursor by a Ni-catalyzed coupling reaction; the microwave-promoted intramolecular aza-Michael addition afforded the imidazo[1,5-a]pyridine core structure of nagelamide K in high stereoselectivity. A detaurine-dediamino a...

An efficient cascade reaction of 2,3-allenoic acids with dialkyl azodicarboxylate in the presence of PPh3 affording 1,2-bis(alkoxycarbonyl)pyrazol-3-ones in moderate yields has been developed. The reaction may proceed via the intramolecular Michael addition of the expected 2,3-allenoyl hydrazines.

One-pot synthesis of heterocycles having a nitromethyl group was achieved by sequential steps that involved chloronitration of alkenes using iron(III) nitrate nonahydrate followed by elimination and intramolecular Michael addition. This reaction provides an efficient method for the synthesis of heterocycles due to the simple experimental procedure and the use of inexpensive reagents of low toxi...

A novel and efficient route for the synthesis of 7-aza-tetrahydroindoles from N-aryl/alkyl-alkenoylacetamides and ethyl isocyanoacetate is described. A mechanism, involving a stepwise [3+2] cycloaddition-intramolecular aza-Michael addition cascade, is proposed that explains the origin of the double nucleophilic attack on the isocyanide carbon atom.

A highly efficient organocatalytic sequential reaction involving Michael addition of bis(phenylsulfonyl)ethylene, in situ condensation and intramolecular nitrone [3+2] cycloaddition with a variety of aldehydes and hydroxyamines to afford a single diastereomer of indanes with four stereogenic centers in excellent yields and stereoselectivities was developed.