Bestmann–Ohira Reagent: A Convenient and Promising Reagent in the Chemical World

Abstract

The Bestmann–Ohira reagent is a unique and versatile reagent in organic synthesis. It is a well‐known homologating agent for the conversion of aldehydes into the corresponding terminal alkynes. Recently, it has also been used as a potent cycloaddition partner in 1,3‐dipolar cycloaddition reactions. The Bestmann–Ohira reagent can be readily accessed from commercially available sources. It has found tremendous application in the regioselective synthesis of a variety of organic synthons, including alkynes, triazoles, triazolines, pyrazoles, oxazoles, thiazoles, isoquinoline N‐oxides, indazoles, pyrroles, and enol ethers in good‐to‐very‐good yields.

Recent Advances in the Construction of Phosphorus‐Substituted Heterocycles, 2009–2019

“…In this context, Namboothiri and co‐workers described a one‐pot base‐mediated regioselective 1,3‐dipolar cycloaddition reaction between diethyl 1‐diazo‐2‐oxopropylphosphonate (Bestmannn–Ohira reagent, BOR) and substituted nitroalkenes such as β‐substituted, α,β‐substituted nitroalkenes and nitroethylene for the synthesis of fused and highly functionalized phosphonylpyrazoles at room temperature . BOR served as a synthetic equivalent of diethyl diazomethylphosphonate (Seyferth–Colvin–Gilbert reagent).…”

Recent advances in catalytic silylation of hydroxyl‐bearing compounds: A green technique for protection of alcohols using Si–O bond formations

“…[92][93][94][95] There are two features: the oxygen atom nucleophilicity in N-oxides and a high affinity of silicon to oxygen which aim at representing perfect properties in order to develop a synthetic methodology based on nucleophilic activation of organosilicon reagents. [96][97][98][99] Due to the N-O bond polarization, one can classify the heteroaromatic N-oxides properties as strong Lewis bases. [100][101][102][103] In this regard, those Lewis base catalysts which possess the pyridine oxide moiety-positioned in a chiral environment-have constituted a specific type of active catalysts.…”

A Novel Approach to Substituted α-Carbamoyl Phosphonates: Useful Reagents for the Horner–Wadsworth–Emmons Olefination

“…12 For our purposes, however, we considered an entirely different disconnection of 2; namely, down to their diazo precursors 5, the simplest of which (5a, R 1 = Me) is known as the Ohira-Bestmann reagent. 13 Such a disconnection was inspired by our recent success involving closely related -diazo--oxosulfones in thermally promoted Wolff rearrangement in the presence of aromatic amines, which gave rise to -sulfonyl acetanilides. 14 Indeed, the Wolff rearrangement of -diazo phosphonates has been realized under Rh(II)-catalyzed 15 as well as thermally promoted 16 conditions, with O-nucleophile trapping of the resulting ketene intermediate 6.…”

“…OCH 2 CH 3 ) 13. C NMR (101 MHz, CDCl 3 ):  = 167.11 (d, J = 3.1 Hz), 132.30 (d, J = 9.6 Hz), 129.46 (d, J = 6.0 Hz), 128.58 (d, J = 2.9 Hz), 127.64 (d, J = 3.5 Hz), 63.41 (d, J = 6.5 Hz), 62.51 (d,…”