tris(pentafluorophenyl)borane, B(C6F5)3, and BF3·Et2O are shown to catalyze the regioselective hydrothiolation of a wide range of terminal 1-aryl-1,3-dienes. In the case of internal 1,3-dienes, B(C6F5)3 is by far the better catalyst than BF3·Et2O. The process features mild reaction conditions, broad scope, and low catalyst loading, and it can be scaled up quickly over a short reaction time. The reactions are rate-limited
报道了用于合成仲和叔烯丙基硫醚的无过渡金属的1,3-二烯氢硫醇化反应。硼路易斯酸三(五氟苯基)硼烷,B(C 6 F 5)3和BF 3 ·Et 2 O已显示出催化范围广泛的末端1-芳基-1,3-二烯的区域选择性氢硫醇化反应。在内部1,3-二烯的情况下,与BF 3 ·Et 2相比,B(C 6 F 5)3是更好的催化剂。O.该工艺的特点是反应条件温和,适用范围广,催化剂用量低,并且可以在较短的反应时间内迅速扩大规模。如高水平DFT计算所示,反应是通过1,3-二烯与硫醇-硼路易斯酸配合物的1-芳基定向质子化,然后将硫化物阴离子转移到所得的烯丙基阳离子上来进行的,从而限制了反应的速率。
Organoselenium-Catalyzed Regioselective C−H Pyridination of 1,3-Dienes and Alkenes
作者:Lihao Liao、Ruizhi Guo、Xiaodan Zhao
DOI:10.1002/anie.201610657
日期:2017.3.13
organoselenium‐catalyzed regioselective C−H pyridination of 1,3‐dienes to form pyridinium salts has been developed. This method was also successfully applied to direct C−H pyridination of alkenes. Fluoropyridinium reagents, or initially loaded pyridine derivatives, acted as pyridine sources in the pyridination reactions. The obtained pyridinium salts could be further converted under different conditions
The hydroboration/Pd-catalyzed migrative Suzuki–Miyaura cross-coupling of 1,3-dienes with electron-deficient arylhalides has been developed, which enables the synthesis of branched allylarenes directly from primary homoallylic alkyl boranes. A ligand-tuned linear- or branch-selective coupling for these arylhalides has also been achieved.
Interception of Nazarov Reactions of Allenyl Vinyl Ketones with Dienes: (3+2)- versus (4+3)-Cycloaddition and Subsequent Rearrangement
作者:Timothy D. R. Morgan、François M. LeFort、Zhe Li、Vanessa M. Marx、Russell J. Boyd、D. Jean Burnell
DOI:10.1002/ejoc.201403618
日期:2015.5
Capture of the cyclic oxyallyl cation intermediates from the BF3-mediated Nazarov reactions of three allenyl vinyl ketones with various dienes was accomplished by (3+2)- and (4+3)-cycloaddition. The relative amounts of these types of products were dependent on the substitution on the diene, and this could be linked to steric hindrance. Treatment of the (3+2)-cycloadditionproducts with BF3·Et2O led mainly
Catalytic Enantioselective 1,2-Diboration of 1,3-Dienes: Versatile Reagents for Stereoselective Allylation
作者:Laura T. Kliman、Scott N. Mlynarski、Grace E. Ferris、James P. Morken
DOI:10.1002/anie.201105716
日期:2012.1.9
More with boron: The development of catalyticenantioselective 1,2‐diboration of 1,3‐dienes enables a new strategy for enantioselective carbonyl allylation reactions (see scheme). These reactions occur with outstanding levels of stereoselection and can be applied to both monosubstituted and 1,1‐disubstituted dienes. The carbonyl allylation reactions provide enantiomerically enriched functionalized