Ring expansion of cyclic 1,2-diols to form medium sized rings via ruthenium catalyzed transfer hydrogenative [4+2] cycloaddition
作者:Zachary A. Kasun、Laina M. Geary、Michael J. Krische
DOI:10.1039/c4cc03983a
日期:——
A new method for the ring expansion of cyclic diols is described. Using improved conditions for the ruthenium(0) catalyzed cycloaddition of cyclic 1,2-diols with 1,3-dienes, fused [n.4.0] bicycles 3a–3r (n = 3–6) are formed, which upon exposure to iodosobenzene diacetate engage in oxidative cleavage to form the 9–12 membered rings 4a–4r.
Alicyclic Ring Structure: Conformational Influence of the CF2 Group in Cyclododecanes
作者:Maciej Skibinski、Yi Wang、Alexandra M. Z. Slawin、Tomas Lebl、Peer Kirsch、David O'Hagan
DOI:10.1002/anie.201105060
日期:2011.11.4
Getting out of the way: In fluorinated cyclododecane structures the CF2 group locates only at corner positions (see picture). This relaxes 1,4‐H,H transannular interactions as a result of C‐CF2‐C angle widening. Misplaced CF2 groups lead to significant ring distortion. It follows that strategic incorporation of CF2 groups has potential as a design feature to introduce order and polarity into organic