The synthesis of nonconjugated cyclohex-3-enones via the regiodivergent cobalt-catalysed Diels-Alder reactions of 2-(trimethylsilyloxy)buta-1,3-diene with alkynes and hydrolysis of the dihydroaromatic intermediates is described. The application of bidentate phosphine ligands versus pyridine-imine ligands led to the regioselective formation of one out of the two possible regioisomeric products when terminal or unsymmetrically substituted alkynes were applied. The cyclohex-3-enone products were isolated mostly in good yields without isomerisation of the carbon-carbon double bond into conjugation based on the mild reaction conditions. The use of acetoxymethyl-substituted alkynes led to the conjugated 4-methylenecyclohex-2-enones after deprotection of the silyl enol ether.

alkynes - catalysis - cobalt - Diels-Alder reaction - dienes - nonconjugation

描述了通过2-（三甲基甲硅烷基氧基）buta-1,3-二烯与炔烃的区域发散性钴催化的Diels-Alder反应和二氢芳族中间体的水解来合成非共轭环己-3-烯酮。当应用末端或不对称取代的炔烃时，二齿膦配体相对于吡啶-亚胺配体的应用导致两种可能的区域异构产物之一的区域选择性形成。根据温和的反应条件，大多数以高收率分离出环己-3-烯酮产物，而没有碳-碳双键异构化成共轭。在甲硅烷基烯醇醚脱保护后，使用乙酰氧基甲基取代的炔烃产生共轭的4-亚甲基环己-2-烯酮。

炔烃-催化-钴-狄尔斯-阿尔德反应-二烯-非共轭