P-Panisene

Salomon has recendy investigated the coi er(I) triflate catalyzed photocycloadditions of allylic alcohols and allylic ethers in an effort to improve the selectivity in photocycloadditions of unactivated al-kenes (equations 103-105,108). ° One particularly interesting case is illustrated in equation (104), where Ae more sterically hindered product is produced as a result of the photocycloaddition of a rigidly held tridentate copper complex. McMurry has also utilized a copper(I) catalyzed [2 + 2] photocycloaddition in the synthesis of -panisene (equation 106)."° Interestingly, the noncatalyzed cycloaddition shown in equation (107), which might also produce a precursor for p-panisene, was unsuccessful. 

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