The CpCo(CO)2-catalyzed cocyclization of 1,2-diethynyl-4-methoxybenzene with alkynes can be applied to the synthesis of ‘spacer’-naproxen [2-(6-methoxybiphenylen-2-yl)propanoic acid] and its 7-methoxy isomer, ‘spacer’-isonaproxen. While unsymmetrical alkynes are incorporated without regioselectivity, the methoxy group in 6-methoxy-2,3-bis(trimethylsilyl)biphenylene directs electrophiles to C-3, thus allowing for regiochemical differentiation between the 2- and 3-positions.
CpCo(CO)2 催化的 1,2-二炔基-4-
甲氧基苯与
炔烃的协同环化反应可用于合成“间隔”奈普洛克斯 [2-(6-甲氧基
联苯-2-基)
丙酸] 及其 7-甲氧基异构体“间隔”伊索奈普洛克斯。虽然不对称
炔烃在反应中并未产生区域选择性,但 6-甲氧基-2,3-双(trimethylsilyl)
联苯中的甲氧基团会将电亲体引导至 C-3,从而实现 2 位和 3 位之间的区域
化学差异。