Synthesis of Chlorinated Bicyclic C-Fused Tetrahydrofuro[3,2-c]azetidin-2-ones

Abstract

Some bicyclic C-fused chlorinated tetrahydrofuro[3,2-c]azetidin-2-ones were prepared by a fairly general route involving Staudinger reaction of allylic/propargylic imidates with dichloroketene followed by highly diastereoselective CuCl/PMDETA-catalyzed 5-exo-trig/dig chlorine atom transfer radical cyclization. An oxepan-fused β-lactam was also prepared similarly by 7-endo-trig cyclization. Synthetic application of the side chain chlorine atom of the products was demonstrated by its substitution in one of the products with azide followed by azide-alkyne click reaction with phenylacetylene to obtain a 1,2,3-triazolyltetrahydrofuro[3,2-c]azetidin-2-one.

Copper Catalyzed Atom Transfer Radical Cyclization Reactions

“…This approach was successfully employed in the total synthesis of the antibacterial agent (±)‐botryodiplodin 20c. A similar reactivity order was found for the cyclization of 44 to give 46 20d and 47 to give 48 (Scheme ) 36. Spiroindoles were also prepared by Cu(PMDETA)Cl catalyzed ATRC of 2‐substituted indole derivatives 20f…”

Chemodiscrimination of Olefin Bonds Through Cross‐Metathesis Reactions – Synthesis of Functionalized β‐Lactam and β‐Amino Acid Derivatives

“…They are useful starting materials for further synthetic transformations and used for the preparation of a set of valuable molecular systems such as amino acids, alkaloids, amino alcohols or heterocycles . The high synthetic value of this type of derivatives is demonstrated by the syntheses and applications of functionalized β‐lactams or some fused bicyclic β‐lactams . For example, opening of the azetidinone ring of various β‐lactam derivatives is considered to be one of the most convenient pathways for the stereocontrolled synthesis of open‐chain or cyclic β 2,3 ‐amino acid derivatives .…”

Direct and Stereoselective Synthesis of Diversely Substituted 2,4‐trans‐(NH)‐Pyrrolidines by Copper(I)‐Catalyzed Radical Cyclization at Low Temperature

“…Our interest in the synthesis of polyhaloalkyl substrates and copper(I)‐catalyzed ATRC,,,, led us to develop a mild and an efficient method for the synthesis of sensitive β‐haloethylalkenyl‐NH‐amines 2a–k (Scheme ) followed by their Cu(I)‐catalyzed radical cyclization reaction to afford β‐chloro‐NH‐pyrrolidines 3a–k having 2,4‐ trans ‐selectivity almost exclusively. Synthesis of the β‐chloropyrrolidine ring as a key structural unit continues to be of considerable interest in recent times due to its presence in many naturally occurring compounds such as cyclochlorotine, islanditoxin, and astins A–C ( 1 ), pharmaceuticals ( 2 ) (Figure ) and materials .…”