Synthesis and Some Cycloaddition Reactions of 2-(Triisopropylsilyloxy)acrolein
作者:Michael Harmata、Uday Sharma
DOI:10.1021/ol006281x
日期:2000.8.1
[reaction: see text]2-(Triisopropylsilyloxy)acrolein is easily prepared by the reaction of triisopropylsilyl triflate and 2-methoxy-2-methyl-[1,3]dioxan-5-one in the presence of triethylamine. This dienophile reacts with selected dienes in the presence of catalytic amounts of scandium triflate to afford products that are formally 4 + 3 cycloadducts. An exception is seen in the case of butadiene, where
Asymmetric Synthesis of Cyclobutanone via Lewis Acid Catalyzed Tandem Cyclopropanation/Semipinacol Rearrangement
作者:Su Yong Shim、Yuna Choi、Do Hyun Ryu
DOI:10.1021/jacs.8b06835
日期:2018.9.12
α-silyloxycyclobutanones possessing a chiral β-quaternary center were synthesized in high yield (up to 91%) with excellent enantio- and diastereoselectivity (up to 98% ee and up to >20:1 dr) through tandemcyclopropanation/semipinacol rearrangement. The synthetic potential of this method was illustrated by conversion of the product to various cyclic compounds such as γ-lactone, cyclobutanol, and cyclopentanone
An acid-catalyzed [4+3] cycloaddition reaction of N-nosyl pyrroles with 2-(tert-butyldimethylsilyloxy)acrolein has been developed. The reaction of 2-(silyloxy)acrolein with N-nosyl pyrrole was catalyzed by Tf2NH, and a regio- and stereoselective reaction with 2-substituted N-nosyl pyrroles leading to tropinone derivatives possessing tetra-substituted carbon centers was also achieved. High regioselectivities
A concise method of constructing polycyclic tropinone frameworks was developed. The single‐step synthesis of polycyclic tropinone consists of an intramolecular [4+3] cycloaddition reaction of N‐nosyl‐pyrrole with oxyallyl cation that was generated in situ by an intermolecular condensation reaction of the nucleophilic functional groups on a tethered pyrrole with the aldehyde of 2‐(silyloxy)‐acrolein
a regulatory role in the peripheral nervous system. In this paper, 6,7-dehydrotropinone which is the key intermediate of scopolamine was synthesized in moderate yield through [4+3] cyclization reaction and Barton deoxygenation reaction. This route has good application prospects with mild reaction conditions, moderate yield and simple operation procedures.