The first synthesis of cyclopropanone acetals from the reaction of Fischer carbene complexes with ketene acetals

Transition metals in organic synthesis: Highlights for the year 2005

“…The mechanism of electrospray ionization was also examined [1583]. Cyclopropanation of ketene acetals with Fischer carbenes at elevated CO pressures was reported [1584]. Chiral cyclopropyl Fischer tungsten carbenes were prepared from alkenylcarbene and lithiated aryloxiranes (Eq.…”

Multi-component reactions involving group 6 Fischer carbene complexes: a source of inspiration for future catalytic transformations

“…The analogous reactions with Fischer alkyl or aryl carbenes have been reported to proceed through a 1,2 nucleophilic addition to finally furnish butyrolactones, 31 although the reaction can be directed to the formation of cyclopropanone acetals when FCCs derived from secondary alcohols are employed. 32 More recently, the corresponding reaction of disubstituted ketene acetals 84 with alkoxy alkenyl FCCs 83 has been studied. In this case, the formation of the lactones coming from the 1,2-addition is completely suppressed and, therefore, 4-aryl-3,4-dihydrocumarines 85 are obtained in moderate to good yields by performing the reaction in THF at 90 1C in a sealed tube 33 (Scheme 22).…”

Lithiation of Chromium and Tungsten Aminocarbene Complexes: An Easy Approach to Functionalized Aminocarbene Complexes

“…Fischer carbene complexes of chromium have proved to be useful starting materials in organic synthesis . Probably the best-known stoichiometric synthetic application of chromium alkoxycarbenes is the thermal reaction with alkynes, giving aromatic dihydroxy derivatives, , and the reaction with alkenes, resulting in cyclopropanation . Formal photochemical [2 + 2] cycloaddition of chromium alkoxy- and aminocarbene complexes for the preparation of cyclobutanones and β-lactams have been employed .…”