Enantiomerically enriched 4-carbomethoxy-3, 4-dimethoxy-2, 5-~ yclohexadien-l-one (1) undergoes a completely diastereoselective (but not enantiospecific) type A photorearrangement at 366 nm to give 6-carbomethoxy-4, 6-dimethoxybicyclo [3.1. 0'~ 6] hex-3-en-2-one (2) in 81% isolated yield. A chiral NMR shift study indicates that. 1 undergoes partial loss of absolute configuration at C (4) during irradiation. ...
![(1R*,5R*,6S*)-6-carbomethoxy-4,6-dimethoxybicyclo[3.1.0]hex-3-en-2-one Structure](https://image.chemsrc.com/caspic/339/136315-15-6.png)