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A rapid assembly of the tetracyclic core of marine diterpenoids related to puupehenone and kampanols featuring a Lewis acid catalyzed [4+2] cycloaddition reaction of 1,3,3-trimethyl-2-vinyl-1-cyclohexene and chromone dienophiles is described.

N-Aryl-β-amino acetates, obtained by opening epoxides with aromatic amines followed by acetylation of the hydroxyl group, were resolved using crude pig liver esterase (PLE) enzyme in DMSO in high enantiomeric excess.

A variety of ketones undergo an allylation reaction with tetra-allyltin in the presence of a catalytic amount of Cu(OTf)2 or Sn(OTf)2. The method was found to be superior to most of the known methods, which are efficient only with aldehydes.

A mild, efficient method utilizing a copper-diamine catalyst at room temperature is reported for the coupling of hindered imidazoles with unsubstituted, ortho-substituted, and bis-ortho-substituted boronic acids in good to excellent yields. Aryl halides do not reaction under these conditions permitting sequential N-arylation reactions.

[Co(P1)], which was designed on the basis of potential hydrogen-bonding interactions in the metal-nitrene intermediate, is a highly active aziridination catalyst with azides. [Co(P1)] can effectively aziridinate various aromatic olefins with arylsulfonyl azides under mild conditions, forming sulfonylated aziridines in excellent yields. The Co-based system enjoys several attributes associated with the relatively low cost of cobalt and the wide accessibility of arylsulfonyl azides. Furthermore, it generates stable dinitrogen as the only byproduct.

Asymmetric version of allylic oxidation of oletins to a1lylic esters is an important transformation, The reaction is performed usually using peresters in the presence of a metal catalyst in a chiral environment. Copper catalyst was mainly used by most of the people. Development in this area has been summarized here in a chronological manner. Initially, a modest asymmetric induction in this reaction was achieved by using a variety of chiraI amino acids. Lately, a variety of chiral ligands have been introduced to obtain high enantiomeric excess (up to 93% ee) in the allylic oxidation of a variety of cyclic oletins. One of the drawbacks of the reaction was longer time ranging from a week to a month for completion. This shortcoming was overcome to some extent by using phenylhydrazineJphenylhydrazone in the reaction mixture. The reason for enhancement in rate of the reaction is not yet clear, but the reaction can now be completed within a day or two without loosing enantioselectivity. Despite so much progress in this area, the reaction is restricted only to cyclic oletins. Acyclic oletins do not give high asymmetric induction.

Enantioselective addition of phenylacetylene to various aldehydes was studied in the presence of inexpensive and commercially available Cinchona alkaloids. A maximum of 85% ee was obtained using cinchonidine in the presence of Ti(O i Pr) 4 .

Aromatic electrophilic substitution reactions such as alkylation, acylation, benzoylation, and sulfonylation were studied in the presence of a catalytic amount of Cu(OTf) 2 and Sn(OTf) 2 . Cu(OTf) 2 was very efficient for alkylation, acylation, and benzoylation reactions. However, in case of sulfonylation reactions, Sn(OTf) 2 gave better results.