The Meyer–Schuster rearrangement of propargylic alcohols is a transformation in organic synthesis known for almost a century. The products of this reaction—α,β-enones and their α-functionalized units—are highly important functional groups for various synthetic transformations. Two modifications of this classical reaction, which involves interception of the intermediate allenol (or its equivalent) by either electrophiles or nucleophiles, have attracted the attention of synthetic organic chemists. This Focus Review provides a detailed description of the development of these two strategies. © 2018 Wiley-VCH Verlag GmbH &amp; Co. KGaA, Weinheim

Beeraiah Baire

Department Of Chemistry

Prabhakararao Tharra

Debayan Roy

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Asian Journal of Organic Chemistry

A formal, highly stereoselective halo-Meyer-Schuster rearrangement of inactivated propargylic acetates to (Z)-α-haloenones has been reported, under metal free conditions. This cascade process involves a new class of intermediate, i.e., α,α-dihalo-β-acetoxyketones and mechanism to generate the α-haloenones, employing water as Lewis base. The outcome of the reaction is temperature-dependent, as room temperature, selectively provides α,α-dihalo-β-acetoxyketones whereas reactions at 100 °C give direct access to α-haloenones. Either type of product can be obtained in excellent yield. A suitable rationale for the observed high Z-selectivity for α-haloenones (based on conformational population) and distinct reaction rates for various N-halosuccinimide (NXS) reagents (based on C-X bond strengths) has also been provided. © 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Chemistry (Weinheim an der Bergstrasse, Germany)

Formal Halo-Meyer-Schuster Rearrangement of Propargylic Acetates through a Novel Intermediate and an Unexampled Mechanistic Pathway

The unconventional reactivity of (Z)-enoate-attached propargylic alcohols in the presence of acids (nucleophilic and non-nucleophilic) was described. This study led to the discovery and development of a new strategy for the collective synthesis of the synthetically useful building blocks α-OMs-, α-OTs-, and α-Cl-enones, as well as 4,5-dioxonoates. The reaction proceeded under very mild conditions and showed a broad substrate scope. © 2017 Wiley-VCH Verlag GmbH &amp; Co. KGaA, Weinheim

Chemistry - A European Journal

Unconventional Reactivity of (Z)-Enoate Propargylic Alcohols in the Presence of Acids

Brønsted acid promoted nucleophilation of propargylic alcohols during the Meyer-Schuster rearrangement (M-S) has been introduced. A novel concept of reverse polarization of the M-S intermediate allenyl cation has been realized by employing a cis-enoate assisted strategy. This idea is well demonstrated by the metal free synthesis of complex, highly functionalized cyclic as well as acyclic α-arylenones. The synthetic importance of the derived products was highlighted by the efficient conversion to biologically relevant molecules such as pyrazoles and 4,5-seco-abietane. © The Royal Society of Chemistry 2016.

Chemical Communications

The: Z -enoate assisted, Meyer-Schuster rearrangement cascade: Unconventional synthesis of α-arylenone esters

An acid promoted, unprecedented cascade [3+2] annulation strategy for the synthesis of complex naphtho- and benzofurans is reported. An alkoxyfuranylallene intermediate (generated from Z-enoate propargylic alcohols via a Meyer-Schuster rearrangement) was employed as the 1,2-bis-electrophile and β-naphthols (phenols) as 1,3-bisnucleophiles. This strategy represents the first cascade and metal free process for the synthesis of naphthofurans and benzofurans from propargylic alcohols. A very broad substrate scope was observed. The synthesized naphtho- and benzofurans were efficiently transformed into the frameworks of the bioactive natural products amycofuran and frondosin B. © The Royal Society of Chemistry.

Regioselective, cascade [3+2] annulation of β-naphthols (resorcinols) with Z-enoate propargylic alcohols: a novel entry for the synthesis of complex naphtho(benzo)furans

We have developed a mild, intramolecular intercepted Meyer-Schuster (M-S) rearrangement for the synthesis of 2-acylfurans from corresponding cis-6-hydroxyhex-2-en-4-ynals. This reaction was found to be very general, and the starting materials are easily accessible. By this methodology the first synthesis of deoxy-nor-abiesesquine B, a sesquiterpene, was also achieved in three steps. The concept of adding two nucleophiles during the M-S rearrangement was introduced. © 2015 American Chemical Society.

Journal	Data powered by TypesetAsian Journal of Organic Chemistry
Publisher	Data powered by TypesetWiley-VCH Verlag
ISSN	21935807
Open Access	No