被在γ位上带有杂原子基团(羟基,烷氧基,卤素,二烷基氨基)或苯基的烃链取代的烯丙基化合物的质谱表现出与C 2 H 4损失相对应的强峰(28a.mu)来自分子离子。这通常是光谱的基峰,这是由于杂原子或苯基基团向中心烯丙碳原子的麦克拉费蒂型转移。在这种过程中,甲基显示出较低的迁移能力。在γ-卤素和γ-羟基酮,烯烃,炔烃或芳烃的光谱中未观察到涉及杂原子基团迁移的这种类型的断裂,并且似乎是烯丙基键的特征。提出了杂原子基团(或苯基)对中心烯丙基碳原子的亲核攻击。
Cobalt-Catalyzed Hydroacylative Dimerization of Allenes Leading to Skipped Dienes
作者:Wei Ding、Yan King Terence Ho、Yasuhiro Okuda、Christopher Kevin Wijaya、Zheng Hao Tan、Naohiko Yoshikai
DOI:10.1021/acs.orglett.9b02465
日期:2019.8.2
A cobalt–diphosphine catalyst has been found to promote a selective 1:2 coupling reaction between aldehydes and allenes to form β,δ-dialkylidene ketones, featuring skipped diene moieties, with high regioselectivities and stereoselectivities. The reaction is distinct from previously reported, rhodium-catalyzed aldehyde–allene 1:2 coupling to afford β,γ-dialkylidene ketones bearing 1,3-diene moieties
heteroatomic group (hydroxy, alcoxy, halogen, dialkylamino) or a phenyl in the γ position exhibits a strong peak corresponding to the loss of C2H4 (28a.m.u.) from the molecular ion. This is commonly the base peak of the spectra and due to a McLafferty type transfer of the heteroatom or phenyl group to the central allenic carbonatom. The methylgroup shows a lower migratory aptitude in such a process. This
被在γ位上带有杂原子基团(羟基,烷氧基,卤素,二烷基氨基)或苯基的烃链取代的烯丙基化合物的质谱表现出与C 2 H 4损失相对应的强峰(28a.mu)来自分子离子。这通常是光谱的基峰,这是由于杂原子或苯基基团向中心烯丙碳原子的麦克拉费蒂型转移。在这种过程中,甲基显示出较低的迁移能力。在γ-卤素和γ-羟基酮,烯烃,炔烃或芳烃的光谱中未观察到涉及杂原子基团迁移的这种类型的断裂,并且似乎是烯丙基键的特征。提出了杂原子基团(或苯基)对中心烯丙基碳原子的亲核攻击。