Expedient access to α,β-difunctionalized azepenes using α-halo eneformamides: application to the one-pot synthesis of 2-benzazepanes

Abstract

The regioselective synthesis of α,β-difunctionalized (alkenyl, aryl, sulfonyl, allyl, or alkynyl) azepenes has been accomplished through α-halo eneformamides. A successful implementation of the vicinal functionalization strategy has led to a one-pot synthesis of 2-benzazepanes whose benzenoid portion is highly functionalized.

Modular synthesis and transition metal-free alkynylation/alkenylation of Castagnoli–Cushman-derivedN,O- andN,S-heterocyclic vinyl chlorides

“…Meanwhile, the synthesis of conjugated dienes of type 6 via a Heck-type coupling protocol could pave the way for the construction of polycyclic morpholines. 14 We were not oblivious to the challenges that belie such transformations seeing as vinyl chlorides such as 4 seldom feature in mild crosscouplings, even under transition metal-catalyzed conditions. This is presumably due to challenges associated with an extremely slow oxidative addition step.…”

α-Haloenamides: Synthesis and Subsequent Transformations

“…All rights reserved. Synthesis 2023, 55,[27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44]…”

Regiocontrolled synthesis of (hetero)aryl and alkenyl dehydropyrrolidines, dehydropiperidines and azepenes by Ru-catalyzed, heteroatom-directed α-C–H activation/cross-coupling of cyclic enamides with boronic acids

“…30 Continuing our quest for expedient-, practical-and complementary-methods for accessing functionalized Department of Chemistry, Central Washington University, Ellensburg, WA 98926, USA. E-mail: TimothyB@cwu.edu azaheterocycles, 24,25,[33][34][35][36][37][38][39][40][41][42][43] and the cognizant of the inherently high reactivity of unfunctionalized cyclic enamides such as V (relative to the corresponding saturated cyclic amine), it was surmised that regioselective sp 2 α-C-H functionalization/crosscoupling of the latter with boronic acids, under ruthenium catalysis, offered an attractive approach (Fig. 2E).…”