Internally hydrogen-bonded chiral methylenenitrones in cycloaddition reactions
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Saudi Digital Library
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ﲤﺖ ﺩﺭﺍﺳﺔ ﺍﳊﻠﻘﻴﺔ - ﺛﻨﺎﺋﻴ ٣،١ ﺍﻹﺿﺎﻓﺔ ﺔﺍﻟ ﻘﻄﺐﻻﺛ ﻨ (chiral) ﲔ ﻣﻦ ﺍﳌﻴﺜﻠﲔ نﻴﱰﻭﻥ ﻏﲑﻣﺘﻤﺎﺛﻠﺔ ﻭﻫﻲ: (R)-N-2-(1-hydoxy-2-phenyl ethyl)methylenenitrone (I) و
(1R,2S,3R,4R)-N-3-(2-hydroxy-1,7,7-trimethylbicyclo[2.2.1]heptanyl)methylenenitrone(II) ﻣﻊ ﺛﻼﺛﻴﺔ ﺃﻟﻜﻴﻨﺎﺕ ﺁﺣﺎﺩﻳﺔ ﻭ ﺛﻨﺎﺋﻴﺔ ﻭ . ﻭﻟﻘﺪ ﺃﻇﻬﺮﺍﻟﻨﻴ ﺍنﺘﻘﺎﺋﻴﺔ(II) ﱰﻭﻥ ً ً ﻭﺟﻬﻴﺔ ﻭ ﺍﲡﺎﻫﻴﺔﺃﻓﻀﻞ .ﺍﻟﻜﻴﻤ ﰎ ﺗﻔﺴﲑ ﺍﻟﻨﺎﺗﺞ ﻴ ﺎﺋﻲ ﺍﻻﲡﺎﻫﻲ ﳍﺬﻩ ﺍﻟﺘﻔﺎﻋﻼﺕ ﺑﻨﺎﺀ ﻋﻠﻰ ﺍﻟﻌﻮﺍﻣﻞ ﺍﻟﻔﺮﺍﻏﻴﺔ ﻭ ﺍﻟﺘﺪﺍﺧﻼﺕ ﺍﳌﺪﺍﺭﻳﺔ ﺍﻟﺜﺎنﻮﻳﺔ ﻟﻠﻤﺮﻛﺒﺎﺕﺍﻻنﺘﻘﺎﻟﻴﺔ . ﻛﻤﺎ ﰎ ﺇﻇﻬﺎﺭ ﻣﺪﻯ ﺍﻟﺮﺍﺑﻄﺔ ﺗﺎﺛﲑ ﺍﳍﻴﺪﺭﻭﺟﻴﻨﻴﺔ ﺍﻟﻮﺍﺣﺪ ﺍﻟﺪﺍﺧﻠﻴﺔ ﺿﻤﻦ ﺍﳉﺰﻳﺊ . ﻭﻟﻘﺪ ﺍﻹ ﺃﻇﻬﺮﺕ ﺿﺎﻓﺔ ﺍﳊﻠﻘﻴﺔﺛﻨﺎﺋﻴﺔﺍﻟﻘﻄﺐ ﻟ ﺍنﺘﻘﺎﺋﻴﺔ (I) ﻠﻨﻴﱰﻭﻥ ﺑﺎﺳﺘﺨﺪﻡ ﳎﻨﻴﺰﻳﻮﻡ ﺍﻟﱪﻭﻣﻴﺪ ﺍﲡﺎﻫﻴﺔ ﻣﻜﺎنﻴﺔ ﻭ ﻣﺘﻤﻴﺰﺓ .ﺑﺮﺭﺕ ﻭﻟﻘﺪ ِ ﺤﺴﱠﻨﺔ ﺑﺎ ُ ﺍﻹنﺘﻘﺎﺋﻴﺔ ﺍﳌ ﺳﺘﻌﻤﺎﻝ ﺷﻜﻞ ﳌ ﺣﻠﻘﻲ ﻌﻘﺪﺍ ﺍﻟﻔﻠﺰ ﻟﻨﻴﱰﻭﻥ ﻣﻊ . ﺇ ﻥ ﺍﻟﻨﺘﺎﺋﺞ ﺍﻟﱵ ﺗﻮﺻﻠﺖﻫﺬ ﻩ ﺍﻟﺪﺭﺍﺳﺔ ﺳﺘﻜﻮﻥ ﺣﻘﺎﺫ ﺍﺕﺃ ﺍﳌﺮﺍ ﳘﻴﺔ ﰲ ﺗﺼﻨﻴﻊ ﻣﺘﻤﺎﺛﻠﺔ (chiral centers) ﻛﺰ ﻏﲑ ﻟﻠﻤﻨﺘﺠﺎﺕ ﺍﻟﻄﺒﻴﻌﻴﺔ