The versatile conversion of lactam to the a-alkylated amines via cyclic N.O-acetal TMS ether

As a part of our continuing studies directed toward the synthesis of the medium to macrolactam alkaloids, we have been interested in the versatile functionalization of the lactam carbonyl. Synthetic routes involving cyclic N-acyliminium ions are generally useful strategies that have been applied for a wide variety of synthetic transformation. Especially, the use of a-alkoxy azacycles as precursors to cyclic N-acyliminium ions was well reviewed. (omitted)