Regioselective construction of polysubstituted benzene ring from Baylis-Hillman adduct via [4+2] annulation strategy

A new and regioselective [4+2] benzannulation protocol toward polysubstituted benzenes was developed. Nitroalkane derivative, which was prepared from Baylis-Hillman adduct, served as the four-carbon unit and Michael acceptor as a two-carbon unit.     

Regioselective synthesis of polysubstituted benzenes from Baylis-Hillman adducts via [4+2] annulation protocol

A new and regioselective [4+2] benzannulation protocol toward polysubstituted benzenes was developed. A nitroalkane derivative, which was prepared from Baylis-Hillman adduct, served as the four-carbon unit and a Michael acceptor as a two-carbon unit. Vinyltriphenylphosphonium salt could also be used as a Michael acceptor efficiently.     

Fast and efficient preparation of Baylis-Hillman-derived (E)-allylic azides and related compounds in aqueous medium

A practical access to alkyl- and aryl-substituted (E)-2-(azidomethyl)alkenoates and related azido compounds from the corresponding allylic bromides in aqueous acetone is described. An alternative method to obtain the starting bromides based on heterogeneous catalysis under mild conditions was also investigated.     

Stereoselective aldol coupling of α,β-acetylenic ketones promoted by MgI2

A highly stereoselective synthesis of (Z)-β-iodovinyl ketone has been achieved with the tandem formation of CC and CI bonds in a three-component reaction. This new catalysis utilizes MgI₂ as a Lewis acid as well as an iodine source for a Michael-type addition. α,β-Acetylenic ketone is initially converted to an active β-iodo allenolate intermediate and then can be attacked by a variety of aldehydes to afford Z-selective Baylis-Hillman adducts in excellent yields.     

Stereoselective synthesis of tri- and tetrasubstituted oxepanes via n-Bu3SnH mediated 7-endo-trig vinyl radical cyclisation

A stereoselective 7-endo-trig cyclisation of homopropargyl and phenyl homopropargyl derivatives of Baylis-Hillman adducts using n-Bu₃SnH/AIBN mediated vinyl radical cyclisation affords tri- and tetrasubstituted oxepanes, respectively, in good yields.     

An acid-catalyzed Michael-aldol reaction

A tricyclic ketone is formed from cyclohexanone and cyclohexenone in strong acid solutions. The structure is confirmed by X-ray crystallography.     

Applications of Baylis-Hillman adducts: a simple, convenient, and one-pot synthesis of 3-benzoylquinolines

A simple and convenient synthesis of 3-(2-hydroxybenzoyl)quinoline derivatives via the treatment of 3-[hydroxy(2-nitroaryl)methyl]-4H-chromen-4-ones, derived from chromones and various 2-nitrobenzaldehydes, with Fe/AcOH, in a one-pot operation, is described.     

Salt effects on the Baylis-Hillman reaction

The Baylis-Hillman reaction is shown to accelerate in salt solutions of water and the ‘water-like’ structured solvents, like formamide and N-methylformamide in the presence of DABCO. Ethylene glycol, another structured solvent and its salt solutions fail to make any impact on the reaction rates. The salts that are conventionally defined as salting-out or -in do not behave in a similar fashion, when employed in the Baylis-Hillman reactions. The results are supported by solubility measurements. It seems that the cation, anion, nature of solvent and of reactants together ascertain whether a salt will enhance or retard the Baylis-Hillman reaction.     

Development of bis-thiourea-type organocatalyst for asymmetric Baylis-Hillman reaction

A new chiral bis-thiourea-type organocatalyst 2 developed for the Baylis-Hillman reaction provided a drastic rate enhancement. Allylic alcohols were obtained with up to 90% ee in the case of cyclohexanecarboxaldehyde (4i).     

Regioselective synthesis of 1-arylnaphthalenes from N-tosylaziridine derivatives

Regioselective synthesis of 1-arylnaphthalene derivatives was carried out from N-tosylaziridines, which was made from the reaction of N-tosylimines and cinnamyl bromides by using the sulfur ylide chemistry.