Enantioselective Organocatalytic Michael Addition of Cyclobutanones to Nitroalkenes
作者:Damien Mailhol、Maria del Mar Sanchez Duque、Wilfried Raimondi、Damien Bonne、Thierry Constantieux、Yoann Coquerel、Jean Rodriguez
DOI:10.1002/adsc.201200658
日期:2012.12.14
Synthetic applications of cyclobutanones other than ring expansion and fragmentation reactions are rare. Herein, highly efficient diastereo- and enantioselectiveorganocatalytic Michael additions of 2-substituted cyclobutanone derivatives to nitroalkenes are reported allowing the stereocontrolled creation of ‘all-carbon’ quaternary centers. The approach relies on both the use of Brønsted base/hydrogen-bond
An enantioselective Michael addition– four‐atom ring expansion cascade reaction involving cyclobutanones activated by a N‐aryl secondary amide group and ortho‐amino nitrostyrenes has been developed for the preparation of functionalized eight‐membered benzolactams using bifunctional aminocatalysts. Taking advantage of the secondary amide activating group, the eight‐membered cyclic products could be
A Lewis Acid-Promoted Michael Addition and Ring-Expansion Cascade for the Construction of Nitrogen-Containing Medium-Sized Rings
作者:Jiaming Wang、Jia Li、Changgui Zhao
DOI:10.3390/molecules28041650
日期:——
A Lewis acid-promoted annulation of azadienes and cyclobutamines was developed. This reaction proceeded through Michael addition and ring-expansion cascade, affording the corresponding nitrogen-containing medium-sized rings with a broad scope in moderate to high yields. The catalytic asymmetric version of this reaction has also been explored using a chiral base.