title: Access to β-lactams by enantioselective palladium(0)-catalyzed C(sp3)-H alkylation.
abstract: β-Lactams are very important structural motifs because of their broad biological activities as well as their propensity to engage in ring-opening reactions. Transition-metal-catalyzed C-H functionalizations have emerged as strategy enabling yet uncommon highly efficient disconnections. In contrast to the significant progress of Pd(0)-catalyzed C-H functionalization for aryl-aryl couplings, related reactions involving the formation of saturated C(sp(3))-C(sp(3)) bonds are elusive. Reported here is an asymmetric C-H functionalization approach to β-lactams using readily accessible chloroacetamide substrates. Important aspects of this transformation are challenging C(sp(3))-C(sp(3)) and strain-building reductive eliminations to for the four-membered ring. In general, the β-lactams are formed in excellent yields and enantioselectivities using a bulky taddol phosphoramidite ligand in combination with adamantyl carboxylic acid as cocatalyst.
authors.affiliation: Laboratory of Asymmetric Catalysis and Synthesis, EPFL SB ISIC LCSA, BCH 4305, 1015 Lausanne (Switzerland) http://isic.epfl.ch/lcsa.
authors.forename: Julia
authors.initials: J
authors.lastname: Pedroni
authors.forename: Michele
authors.initials: M
authors.lastname: Boghi
authors.forename: Tanguy
authors.initials: T
authors.lastname: Saget
authors.forename: Nicolai
authors.initials: N
authors.lastname: Cramer
mesh_terms: D000478:Alkylation; D002384:Catalysis; D010165:Palladium / Q000737:chemistry*; D013237:Stereoisomerism; D047090:beta-Lactams / Q000737:chemistry*
chemical_list: D047090:beta-Lactams; D010165:Palladium
keywords: CH activation; asymmetric catalysis; cross coupling; lactams; palladium