A practical and effective copper-catalyzed dehydrogenative Diels–Alderreaction of gem-diesters and ketone with dienes has been established. The active dienophiles were generated in situ via a radical-based dehydrogenation process, which reacted with a wide variety of dienes to afford various polysubstituted cyclohexene derivatives in good to excellent yields.
The use of microwaveheatingtechnique for the acceleration of ortho ester Claisen rearrangement (a three step transformation) is described. Irradiation of a DMF solution of the allyl alcohol , triethyl orthoacetate and propionic acid (catalytic) in an Erlenmeyer flask for 10 minutes in a microwave oven generated the ester in 83% yield. Analogously, ortho ester Claisen rearrangement of a variety of
Construction of Oxa-Bridged Tetracyclic Frameworks through a Prins Bicyclic Annulation
作者:Preethi N. Nair、Vangala Swathi、Ghaytadak Nishigandha、Balasubramanian Sridhar、Jithender G Reddy、Basi V. Subba Reddy
DOI:10.1002/ejoc.201801788
日期:2019.6.16
Aldehydes undergo smooth condensation with enediols in the presence of TMSOTf in dichloromethane to afford the corresponding hexahydro‐8a,4a‐(epoxyethano)pyrano[3,4‐f]isoindole‐1,3(2H,5H)‐dione derivatives in good yields.
在二氯甲烷中,在TMSOTf存在下,醛与烯二醇进行平滑缩合,得到相应的六氢-8a,4a-(环氧乙烷基)吡喃并[3,4- f ]异吲哚-1,3(2 H,5 H)-二酮衍生物良品率高。
Reaction Control in Synthetic Organic Photochemistry: Switching between [5+2] and [2+2] Modes of Cycloaddition
作者:Claudio Roscini、Kara L. Cubbage、Malcolm Berry、Andrew J. Orr-Ewing、Kevin I. Booker-Milburn
DOI:10.1002/anie.200904059
日期:2009.11.2
Split personality: Reaction conditions that enable powerful control over the mode of photocycloaddition in maleimides have been developed. Direct irradiation favors the [5+2] mode whereas sensitized irradiation allows a complete switch to the [2+2] mode (see scheme; TBS=tert‐butyldimethylsilyl).