Synergistic control over the SH2 transition states of hydrogenabstraction exploiting polar and steric effects provides a promising cooperative strategy for site‐selective C(sp3)−H functionalization using decatungstate anion photocatalysis. By using this photocatalytic approach, the C−H bonds of substituted lactones and cyclic ketones were functionalized selectively. In the remarkable case of 2‐isoamyl
利用极性和空间效应对氢提取的S H 2过渡态进行协同控制,为利用去阳离子化阴离子光催化的位点选择性C(sp 3)-H功能化提供了一种有前途的合作策略。通过使用这种光催化方法,取代的内酯和环状酮的CH键被选择性地官能化。在带有5个甲基,5个亚甲基和3个次甲基CH键的2-异戊基4-叔丁基环己酮(1 t)的显着情况下,异戊基绳索中的1个次甲基CH键被选择性地官能化。
Site-selectivity in TBADT-photocatalyzed C(sp<sup>3</sup>)–H Functionalization of Saturated Alcohols and Alkanes
Site-selectivity in C(sp3)–H functionalization of aliphatic alcohols and alkanes was studied using the decatungstate anion as a photocatalyst. In the case of aliphatic alcohols, C–H bond α to the hydroxy group was preferentially functionalized. The α-site-selectivity is rationalized by polar effects imparted by the hydroxy group in the SH2 transition states. In contrast, C–H functionalization of alkanes was largely affected by steric effects.
A mild biosynthesis of lactones via enantioselective hydrolysis of hydroxynitriles
作者:Julie A. Pollock、Karen M. Clark、Bethany J. Martynowicz、Matthew G. Pridgeon、Matthew J. Rycenga、Kristen E. Stolle、Stephen K. Taylor
DOI:10.1016/j.tetasy.2007.07.034
日期:2007.8
We have developed a biocatalytic method to produce lactones and related compounds via the enzymatic hydrolysis of γ- and β-hydroxynitriles. The synthesis is a mild, general, and environmentally friendly way to enantioselectively hydrolyze nitriles with commercially available nitrilase enzymes. The synthesis of four pheromones is demonstrated via a one-step method.