Amides are not only a class of cheap and readily available feedstocks, but also important synthetic intermediates. Due to the high stability of amides, their transformation generally required multistep. The direct and chemoselective transformation of amides under mild conditions is highly desirable to approach step economy. However, it is quite challenging. In 2010, a general one-pot method for the direct conversion of lactams and amides into tertiary tert-alkyl-amines was developed by Huang et al. Since them, a handle of versatile methods for the chemoselective and direct transformation of amides have been developed from Huangʼs group in the last decade. The applicability of Huang’s amide-activation-annulation, reductive bis-alkylation of lactams/amides, direct transformation of secondary amides to nitriles, the reduction of amides with Tf₂O/ NaBH₄, among others, have been demonstrated by other research groups through the employment of Huangʼs methods to resolve their synthetic challenges. In this paper, formal total synthesis of (–)-sedacryptine (1) and total synthesis of (–)- Geissman-Waiss lactone derivative (3aS,6aS)-4-(4-methoxybenzyl)hexahydro-2H-furo[3,2-b]pyrrol-2-one (9) and (3aS,7aS)-4- (4-methoxybenzyl)hexahydrofuro[3,2-b]pyridin-2(3H)-one (10) have been achieved in seven steps and four steps. The strategy relies on the chemoselective one-pot Knoevenagel-type reaction of amides and iridium, and B(C₆F₅)₃ co-catalyzed deoxygenative reduction of tertiary amides developed from Huangʼs laboratory.

Key words: amide, Knoevenagel-type reaction, iridium and B(C₆F₅)₃ co-catalyzed reduction, (–)-Sedacryptine, (–)-Geiss- man-Waiss lactone