A novel cycloisomerization reaction of enynes 4 in the
presence of ZnBr2 and THF (1 eq.) in
CH2Cl2 at −40 °C gave
exo-methylenic 1,3-dienes 5 in moderate to good yield.
Enabling Wittig reaction on site-specific protein modification
作者:Ming-Jie Han、De-Cai Xiong、Xin-Shan Ye
DOI:10.1039/c2cc35738k
日期:——
An efficient aqueous Wittigreaction was enabled on protein bioconjugation for the first time. By investigating the reaction on small molecules, peptides, and proteins, a site-specific reaction targeting "aldehyde tag" was presented. A variety of functional groups could be introduced into the protein of interest.
Lewis acid-promoted cyclizations of heteroatom-substituted enynes have been examined. The reaction of enynes 3 and 7 bearing silicon substituents on an alkyne afforded the halogenated five-membered γ-lactones 4 and γ-lactams 8 as the main products. The reaction of substrates 15 and 16 having 2-phosphonoacrylate instead of malonate also gave halogenated five-membered cyclic compounds 17 and 18 as the major products. The cyclized products are highly substituted and potentially useful for further synthetic transformations.