A Common Synthetic Protocol for the Cyclic and Acyclic Core of Migrastatin, Isomigrastatin, and Dorrigocin via a Chiral β‐Hydroxy‐γ‐butyrolactone Intermediate

Abstract

A novel approach to agrochemically important difluoromethyl‐substituted pyrazoles has been developed based on the elusive reagent CF2HCHN2, which was synthesized (generated in situ) for the first time and employed in [3+2] cycloaddition reactions with alkynes. The reaction is extremely practical as it is a one‐pot process, does not require a catalyst or the isolation of the potentially toxic and explosive gaseous intermediate, and proceeds in a common solvent, namely chloroform, in air. The reaction is also scalable and allows for the preparation of the target pyrazoles on gram scale.

Synthesis of 1,4-Diazepanes and Benzo[b][1,4]diazepines by a Domino Process Involving theIn SituGeneration of an Aza-Nazarov Reagent

“…An alternative mechanism involving the initial isomerization of 2 to yield a conjugated enone was discarded because these starting materials were shown to be stable in the usual reaction conditions in the absence of the diamine 1 . Also, it is relevant to note in this regard that ethyl 3-oxo-4-pentenoate has been employed as the starting material for a variety of synthetic transformations, always without isomerization …”

Natural Product Inspired Topology Directed Synthesis of Hybrid Macrocyclic Compounds: A Simple Approach to Natural Product Analogues

“…Accordingly, tetrahydrofuran moiety in amphidinolide T was prepared from alcohol 21 in 6 steps using the established protocols yielded the inseparable diastereomeric mixture (4:1) of ester 25 which up on hydrolysis gave acid 6 (Scheme ) ,. The fragment 22 was prepared from 23 in 2 steps (Scheme ) ,…”

The Potential of β‐Hydroxy‐γ‐vinyl‐γ‐lactone in the Synthesis of Natural Products and Beyond

“…The pure lactones were studied for Pd‐catalyzed γ‐epimerization; though the diastereomer ratio was not very promising, these were separable by column chromatography. A racemic synthesis of (±)‐ 1 was reported by Gade and Iqbal (Scheme B). The addition of allyl bromide to the ester‐cyanide 18 gave the β‐keto ester 19 .…”