A conjugate addition/asymmetric protonation/aza-Prins cascade reaction has been developed for the enantioselective synthesis of fused polycyclic indolines. A catalyst system generated from ZrCl4 and 3,3'-dibromo-BINOL enables the synthesis of a range of polycyclic indolines in good yields and with high enantioselectivity. A key finding is the use of TMSCl and 2,6-dibromophenol as a stoichiometr...

An atom-economic synthetic route to benzimidazolium salts is presented. The annulated polycyclic systems: 1,3-bis(2,4,6-trimethylphenyl)-1H-benzo[d]imidazol-3-ium chloride (1-Cl), 1,3-bis(2,6-diisopropylphenyl)-1H-benzo[d]imidazol-3-ium chloride (2-Cl), 1,3-diphenyl-1H-benzo[d]imidazol-3-ium chloride (3-Cl), and 1,3-di(pyridin-2-yl)-1H-benzo[d]imidazol-3-ium chloride (4-Cl) were prepared in a t...

SYNLETT 2004, No. 6, pp 1054–105806.05.2004 Advanced online publication: 25.03.2004 DOI: 10.1055/s-2004-822895; Art ID: G04404ST © Georg Thieme Verlag Stuttgart · New York Abstract: Using only 10% of CrCl2 as catalyst, manganese-powder as reducing agent and TMSCl as scavenger, 2-methylene-a,w-dialdehydes and -ketones can be coupled to form cyclic diols diastereoselectively. The diastereomeric e...

efficient and chemoselective protection of aldehydes to the corresponding dimethyl acetals have been carried out by mixture of trimethyl orthoformate and methanol in the presence of a catalytic amount of tmscl or alcl3 under microwave irradiation. under these conditions, acetalization of ketones does not take place and they remain intact under reaction conditions. the results are compared with ...

Three-component reactions have emerged as useful methods because the combinationof three components to generate new products in a single step is extremely economical,among the multi-component reactions. A green, simple, efficient, and cost-effective procedure has been carried out by the synthesis of dihydropyrimidinonesin Biginelli’s condensation of ethyl cyanoacetate, aldehyde and urea or thio...

Efficient and chemoselective protection of aldehydes to the corresponding dimethyl acetals have been carried out by mixture of trimethyl orthoformate and methanol in the presence of a catalytic amount of TMSCl or AlCl3 under microwave irradiation. Under these conditions, acetalization of ketones does not take place and they remain intact under reaction conditions. The results are compared with ...