Synthesis 2018; 50(11): 2163-2180
DOI: 10.1055/s-0036-1591986
short review
© Georg Thieme Verlag Stuttgart · New York

Cp2Ti(III)Cl and Analogues as Sustainable Templates in Organic Synthesis

José Manuel Botubol-Ares †
a   Departamento de Química Orgánica, Facultad de Ciencias, Campus Universitario Río San Pedro s/n, Universidad de Cádiz, Torre Sur, 4ª planta, 11510, Puerto Real, Cádiz, Spain   eMail: Isidro.gonzalez@uca.es
,
María Jesús Durán-Peña †
a   Departamento de Química Orgánica, Facultad de Ciencias, Campus Universitario Río San Pedro s/n, Universidad de Cádiz, Torre Sur, 4ª planta, 11510, Puerto Real, Cádiz, Spain   eMail: Isidro.gonzalez@uca.es
,
James R. Hanson
b   Department of Chemistry, University of Sussex, Brighton, Sussex BN1 9QJ, UK
,
Rosario Hernández-Galán
a   Departamento de Química Orgánica, Facultad de Ciencias, Campus Universitario Río San Pedro s/n, Universidad de Cádiz, Torre Sur, 4ª planta, 11510, Puerto Real, Cádiz, Spain   eMail: Isidro.gonzalez@uca.es
,
a   Departamento de Química Orgánica, Facultad de Ciencias, Campus Universitario Río San Pedro s/n, Universidad de Cádiz, Torre Sur, 4ª planta, 11510, Puerto Real, Cádiz, Spain   eMail: Isidro.gonzalez@uca.es
› Institutsangaben
Financial support for this research was provided by grants from MINECO­ (AGL2015-65684-C2-1-R and BFU2015-68652-R).
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Publikationsverlauf

Received: 10. Januar 2018

Accepted after revision: 16. März 2018

Publikationsdatum:
03. Mai 2018 (online)


These authors contributed equally to this work

Abstract

This short review aims to provide an overview of the use of Cp2Ti(III)Cl and other related titanocene(III) species as coordinating reagents­ in template reactions in the selective preparation of C–C and C–O bonds. These complexes are able to assemble two components to produce powerful reactions possessing high regio-, chemo-, diastereo-, and enantioselectivity. The titanocene templates are divided into five structural types. The chemical transformations by these valuable templates, the substrate scope and mechanistic insights will also be described.

1 Introduction

2 Precedents for the Coordination of Ti(III) Species to Heteroatoms

2.1 Coordination of Compounds with Hydrogen–Heteroatom Bonds to Ti(III) Species

2.2 Coordination of Halogens to Ti(III) Species

3 Types of Titanocene Templates

4 Template Type I Mediated Organic Reactions

4.1 Methylenecyclopropanation of Allylic Alcohols

4.2 Base-Free O-Acylation of Alcohols and Phenol

4.3 Epoxidation of Allylic Alcohols

5 Template Type II Mediated Organic Reactions

5.1 Ketone–Nitrile Cross-Coupling Reactions

5.2 Imine–Nitrile Cross-Coupling Reactions

5.3 Reductive Alkylation of Enones with Activated Alkenes

6 Template Type III Mediated Organic Reactions

6.1 Pinacol Coupling of Ketones

7 Template Type IV Mediated Organic Reactions

7.1 Michael-Type Addition of Aldehydes to Conjugated Enals

7.2 Allylation, Crotylation, and Prenylation

7.3 Barbier-Type Progargylation and Allenylation

8 Template Type V Mediated Organic Reactions

8.1 Protection of Alcohols as 2-O-THF and 2-O-THP Ethers

8.2 Pinacol Coupling of Aldehydes

8.3 McMurry Couplings

9 Conclusions and Perspectives