Generation and hetero-Diels-Alder reactions of an o-quinone methide under mild, anionic conditions: rapid synthesis of mono-benzannelated spiroketals.
Deprotonation of o-hydroxybenzyl acetate with (i)PrMgCl provides a method of generating an o-quinone methide under mild, anionic conditions, such that highly sensitive exo-enol ethers can be employed as 2pi partners in hetero-Diels-Alder reactions. This process results in mono-benzannelated spiroketals such as those found in the natural products berkelic acid, the chaetoquadrins or cephalostatin 6.
Bray
Christopher D
CD
School of Biological and Chemical Sciences, The Walter Besant Building, Queen Mary, University of London, London, UK. c.bray@qmul.ac.uk
D000838:Anions / Q000737:chemistry; D001555:Benzene Derivatives / Q000138:chemical synthesis / Q000737:chemistry*; D005663:Furans / Q000138:chemical synthesis*; D045563:Indolequinones / Q000138:chemical synthesis / Q000737:chemistry*; D015394:Molecular Structure; D011522:Protons; D013141:Spiro Compounds / Q000138:chemical synthesis*
D000838:Anions; D001555:Benzene Derivatives; D005663:Furans; D045563:Indolequinones; D011522:Protons; D013141:Spiro Compounds; C520774:spiroketal; C068040:quinone methide