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Ash Ketchum must convince Drew that the rare, Molecule 58 exists. But how? Ash had just been studying this concept before he went out to talk to Drew, believing that he might ask about it. Some people believe that there might be other ways for this molecule to react, but that is untrue. There is only one way for it to evolve due to special stereo- and regiochemical properties. |
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Explain the stereo- and regiochemistry observed for the transformation from 58 to 59.
Step 1: Iodonium dicollidine perchlorate (IDCP) is used to form an iodonium ion that prepare the molecule to be attacked by the TMSCH2SO2NH2. This compound can only attack from below and at carbon 1 because of sterics.TMSCH2SO2NH2 is too big and the molecule is too crowded for it to come from the top or at carbon 2.
Step 2: The HSCH2CH3 can only attack from the top. The previously added TMSCH2SO2NH makes it impossible for HSCH2CH3 to attack carbon 2 from the bottom for an Sn2 reaction. Thus, it will attack from the top at carbon 1 to form equatorially in an Sn2 reaction. The electron pair of the nitrogen on te TMSCH2SO2NH will simultaneously, while acting as a leaving group, attack from the bottom at carbon 2, which pushes the I- off. Overall, there is only one possible formation. There aren't any regio- or stereoisomers formed due to the properties of this mechanism. The nitrogen does an aryl shift from carbon 1 to carbon 2 since it is close enough to attack carbon 2 for an Sn2 reaction [Home] [1H-NMR] [Mechanism] [Leading Questions] [Experimental] [References] [About Us] |
