Intramolecular Cycloaddition Reactions of cis-1,2-Dihydrocatechol Derivatives Incorporating C3-Tethered Diazoketones, Nitrile Oxides, and Azides: Stereocontrolled Routes to Enantiomerically Pure Spiro[5.5]undecanes and Related Systems

Abstract

A series of enantiomerically pure cis-1,2-dihydrocatechol derivatives incorporating C3-tethered diazoketone, nitrile oxide, or azide residues has been prepared from the precursor iodide 7 using Negishi cross-coupling reactions. Such derivatives, including diazoketone 12, participate in regio- and stereo-selective intramolecular cycloaddition reactions to give adducts, for example, 15, that are readily elaborated to spiro[5.5]undecanes such as 18.

The Exploitation of Enzymatically‐Derived cis‐1,2‐Dihydrocatechols and Related Compounds in the Synthesis of Biologically Active Natural Products

“…Intramolecular [2+1], [2+2] and [3+2] cycloaddition reactions have also been developed, with the substrates required for such processes normally being prepared using Negishi cross‐coupling chemistry . So, for example, acetonide 136 could be coupled (Scheme ) with the organozinc compound 173 and so forming ester 174 (83 %) that was readily converted, via the corresponding acid, into the diazoketone 175 (80 %).…”