use | tert-butyl sulfinamide as a chiral auxiliary has the following advantages: (1) it is easy to form imines with various aldehydes or ketones;. (2) Due to the activation of tert-butyl sulfinyl, the generated imine has stronger electrophilicity and is easier to react with nucleophiles or be reduced by metal boron reagents, induce high diastereoselectivity; (3) In the addition product, tert-butyl sulfonyl is also a good protective group, which can withstand strong bases and transition metals in the reaction; (4) Under acidic conditions, tert-butyl sulfonyl groups are easily removed, and the obtained hydrochloride can be purified with ether solvents, and the yield is almost quantitative. Synthesis of 4-sulfonyliminopiperidine, and it can react with benzyl Grignard reagent to form an important pharmaceutical structural unit 4-benzyl-4-aminopiperidine. 1 can also be used to insert methylene into derivatized sulfonylimide to prepare spirotoluenesulfonyl azepine. |