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Various natural products are derived by using newly developed [alpha]-flurorination method and an activated ketene enolate, produced by acid chloride, has reacted with an electrophilic fluorine source (NFSi). Quenching the reaction with a nucleophilic natural product has produced [alpha]-fluorinated carbonyl derivatives of select chemotherapeutics, antibiotics and other pharmaceuticals.

A catalytic, highly enantioselective [alpha]-fluorination of acid chlorides is described to produce products of broad scope and in excellent yields. The power of this new method is shown in a broad range of different derivatives that can be prepared depending on the work up conditions, fluorinated carboxylic acids, amides, esters and peptides are all accessible depending on the nucleophile used to quench the reaction.

The cooperative Lewis acid and base systems are analyzed to explain the significance of various bifunctional asymmetric catalytic methods. The coordination and activation of an electrophile by a Lewis acid is shown to lead to an increase in the yields and reaction rates of the system.

A catalytic, asymmetric process for the synthesis of 1,4-benzoxazinones from o-benzoquinone imides and ketene enolates in presence of cocatalyst Sc[(OTf).sub.3] which increased the yield by 42% is reported.

An examination into the derivatization of various natural products using newly developed α-fluorination methodology is disclosed. An activated ketene enolate, generated from an acid chloride, is allowed to react with an electrophilic fluorine source (NFSi). Quenching the reaction with a nucleophilic natural product produces biologically relevant α-fluorinated carbonyl derivatives of select chemotherapeuties, antibiotics, and other pharmaceuticals. [ABSTRACT FROM AUTHOR]

The article discusses the catalytic, asymmetric α-fluorination of acid chlorides and dual metal— ketene enolate activation. It states that a catalytic highly enantioselective α-fluorination of acid chlorides exploits dual activation strategy. It mentions that dual activation is demonstrated in the broad range of different derivatives that can be synthesized depending on the work up conditions including fluorinated carboxylic acids, amides, esters and peptides.

The catalytic, enantioselective, [4 + 2] cycloaddition reaction of ortho-quinone methides with silyl ketene acetals is described. This mechanistically interesting reaction, initiated by a chiral cinchona alkaloid-derived ammonium fluoride "precatalyst" complex, affords a variety of alkyl- and aryl-substituted 3,4-dihydrocoumarin products in excellent yield and with good enantioselectivity.