Tandem Brønsted Acid Promoted and Nazarov Carbocyclizations of Enyne Acetals to Hydroazulenones
作者:Luz Escalante、Carlos González-Rodríguez、Jesús A. Varela、Carlos Saá
DOI:10.1002/anie.201205823
日期:2012.12.3
Ring the changes: Enyne acetals were easily converted into hydroazulene skeletons by a new and efficient metal‐free route involving a Brønsted acid promoted carbocyclization and a subsequent stereospecific Nazarov cyclization (see scheme). The versatility of this transformation also allowed assembly of interesting heteroaromatic tricyclic systems.
Vinyl radicals, generated from the reaction of vinyl iodides with tributylstannyl radical, react with electron-deficient alkenes to give di- or trisubstitutedalkenes in moderate to good yields. The stereoselectivity is largely dependent on the substituent at 1- and 2-position of vinyl iodides.
Iridium-Catalyzed Enantioselective Hydrogenation of Alkenylboronic Esters
作者:Adnan Ganić、Andreas Pfaltz
DOI:10.1002/chem.201200246
日期:2012.5.29
iridium complex derived from a phosphino–imidazoline ligand is a highly efficient catalyst for the asymmetric hydrogenation of terminal vinyl boronic esters (see scheme). On the other hand, trisubstituted alkenyl‐boronates can be reduced with high activity and good to excellent enantioselectivity employing a pyridine–phosphinite ligand.
A convenient hydroiodination of alkynes using I2/PPh3/H2O and its application to the one-pot synthesis of trisubstituted alkenes via iodoalkenes using Pd-catalyzed cross-coupling reactions
作者:Shin-ichi Kawaguchi、Yuhei Gonda、Haruna Masuno、Huệ Thị Vũ、Kotaro Yamaguchi、Hiroyuki Shinohara、Motohiro Sonoda、Akiya Ogawa
DOI:10.1016/j.tetlet.2014.10.039
日期:2014.12
A facile hydroiodination of alkynes using readily-available reagents such as I2, PPh3, and H2O has been developed. This is extended to the one-pot synthesis of trisubstituted alkenes from alkynes via iodoalkenes using Pd-catalyzed cross-coupling and related methods such as the Suzuki–Miyaura cross-coupling, Sonogashira cross-coupling reaction, and Mizoroki–Heck reaction.