Synthesis of cage [4.4.2]propellanes and D3 -trishomocubanes bearing spiro linkage

Abstract

Abstract: The synthesis of substituted cage [4.4.2]propellanes and D3-trishomocubanes bearing spiro linkage have been assembled with the aid of Diels–Alder reaction and ring-rearrangement as key steps. Here, readily available 1,4-hydroquinone, isoprene, spiro[2.4]hepta-4,6-diene and spiro[4.4]nona-1,3-diene were used as starting materials. The unusual rearrangement of cage propellanes with zinc/acetic acid produced D3-trishomocubanes in good yields. Graphical Abstract: Several cage [4.4.2]propellanes and D3-trishomocubanes have been assembled by Diels–Alder reaction (DA), [2+2] photocycloaddition, and acid-promoted rearrangement. Ring-rearrangement was observed in cage [4.4.2]propellane framework during the acid catalyzed reaction. Rearrangement approach provide new opportunities to construct unusual polycycles.[Figure not available: see fulltext.]