Synthesis of 3,5,6-trisubstituted α-pyrones from Baylis-Hillman adducts

3,5,6-Trisubstituted α-pyrones were synthesized starting from the Baylis-Hillman adducts. The synthesis was carried out via the sequential introduction of ketone at the primary position of Baylis-Hillman adduct, lactonization, and the following oxidation with PCC.     

A novel ytterbium/perfluoroalkylated-pyridine catalyst for Baylis-Hillman reaction in a fluorous biphasic system

Ytterbium perfluorooctanesulfonate [Yb(OPf)₃] catalyses the highly efficient Baylis-Hillman reaction in the presence of a catalytic amount of a novel perfluoroalkylated-pyridine as a ligand in a fluorous biphasic system (FBS) composed of toluene and perfluorodecalin. The new process can be carried out successfully without the use of a stoichiometric amount of Lewis base. The fluorous phase containing the active catalytic species is easily separated and can be reused several times without significant loss of catalytic activity.     

Metallic samarium and iodine promoted facile and efficient syntheses of trisubstituted alkenes from the acetates of Baylis-Hillman adducts

Promoted by samarium metal in the presence of a catalytic amount of iodine, the Baylis-Hillman adducts underwent reductive elimination to form (E)-methylcinnamic ester derivatives. When the iodine was used in 1:1 ratio with metallic samarium, stereospecific syntheses of allylic iodide derivatives, (2Z)-2-(iodomethyl)alk-2-enoates, were achieved. Thus, this gives a new approach to the selective construction of stereo-defined trisubstituted alkenes with the simple Sm/I₂ system.     

Regioselective construction of polysubstituted phenols from Baylis-Hillman adducts via formal [4+2] annulation strategy

Polysubstituted phenol derivatives were synthesized regioselectively starting from the Baylis-Hillman adducts via the formal [4+2] annulation protocol as the key step.     

Expeditious synthesis of 3-arylidenelactams and 3-arylidenelactones from N-tosylaziridine derivatives

An expeditious synthetic method of 3-arylidenelactams was developed starting from N-tosylaziridines, which were made from the reaction of N-tosylimines and cinnamyl bromides by using the sulfur ylide chemistry. The regioselective ring-opening reaction of N-tosylaziridines with anilines, as external nucleophiles, and the following lactamization afforded 3-arylidenelactams. In the absence of external nucleophiles, intramolecular lactonization occurred to afford 3-arylidenelactones.     

Synthesis of 3,4-disubstituted 2(1H)-quinolinones via intramolecular Friedel-Crafts reaction of N-arylamides of Baylis-Hillman adducts

3,4-Disubstituted 2(1H)-quinolinones were synthesized starting from the Baylis-Hillman adducts via the following sequential processes: (i) hydrolysis of the Baylis-Hillman adduct to acid, (ii) EDC coupling with anilines, (iii) H₂SO₄-assisted intramolecular Friedel-Crafts cyclization, and the final (iv) DBU-mediated isomerization.     

A facile one-pot three-component synthesis of ferrocene-grafted dispiro pyrrolidine/pyrrolizidine scaffolds through intermolecular [3+2] cycloaddition reaction of ferrocenyl Baylis-Hillman adduct

A one-pot synthesis of ferrocene-grafted dispiropyrrolidine/pyrrolizidine scaffolds has been accomplished in good yields through a facile 1,3-dipolar cycloaddition of various azomethine ylides derived from diketones and secondary amino acids with Baylis-Hillman adduct derived from ferrocene carbaldehyde. The regiochemical and stereochemical outcomes of the cycloaddition reaction were ascertained by X-ray crystallographic studies of one of the cycloadducts.     

Synthesis of 3-aryl-3-hydroxypyrrolidin-2-ones and 2-benzyl-9b-hydroxy-3,3a,5,9b-tetrahydro-2H-pyrrolo[3,4-c]quinoline-1,4-dione derivatives from the Baylis-Hillman adducts of isatins

We prepared some 3-aryl-3-hydroxypyrrolidin-2-ones and tricyclic 2-benzyl-9b-hydroxy-3,3a,5,9b-tetrahydro-2H-pyrrolo[3,4-c]quinoline-1,4-diones starting from the Baylis-Hillman adducts of isatin derivatives.     

Synthesis of 2-amino-2,3-dihydrobenzofurans and fully substituted furans from modified Baylis-Hillman adducts

Syntheses of 2-amino-2,3-dihydrobenzofuran derivatives 3a-g and fully substituted furans 5a-f were achieved starting from the Baylis-Hillman adducts. We prepared 2-amino-2,3-dihydrobenzofurans from the Baylis-Hillman adducts of methyl and ethyl acrylates and fully substituted furans from the Baylis-Hillman adducts of alkyl vinyl ketones.     

Sequential Baylis-Hillman/RCM protocol for the stereoselective synthesis of (+)-MK7607 and (+)-streptol

Sequential Baylis-Hillman/ring-closing metathesis (RCM) approach toward the total synthesis of (+)-MK7607 and (+)-streptol starting from (R,R)-tartaric acid is reported.