Asymmetric cycloadditions of o-quinone methides employing chiral ammonium fluoride precatalysts.
نویسندگان
چکیده
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.
منابع مشابه
Asymmetric Synthesis of 2,3‐Dihydrobenzofurans by a [4+1] Annulation Between Ammonium Ylides and In Situ Generated o‐Quinone Methides
A highly enantio- and diastereoselective [4+1] annulation between in situ generated ammonium ylides and o-quinone methides for the synthesis of a variety of 2,3-dihydrobenzofurans has been developed. The key factors controlling the reactivity and stereoselectivity were systematically investigated by experimental and computational means and the energy profiles obtained provide a deeper insight i...
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ورودعنوان ژورنال:
- Organic letters
دوره 10 21 شماره
صفحات -
تاریخ انتشار 2008