Synthesis of 1-[bis(trifluoromethyl)phosphine]-1'-oxazolinylferrocene ligands and their application in regio- and enantioselective Pd-catalyzed allylic alkylation of monosubstituted allyl substrates.

Zeng-Wei Lai,Rong-Fei Yang,Hongbin Sun,Shu-Li You,Ke-Yin Ye

doi:10.3762/bjoc.10.126

Abstract

A class of novel, easily accessible and air-stable 1-[bis(trifluoromethyl)phosphine]-1’-oxazolinylferrocene ligands has been synthesized from ferrocene. It became apparent that these ligands can be used in the regio- and enantioselective Pd-catalyzed allylic alkylation of monosubstituted allyl substrates in a highly efficient manner. Excellent regio- and enantioselectivity could be obtained for a wide range of substrates.

Highlights

The palladium-catalyzed asymmetric allylic alkylation (AAA) reaction is becoming an efficient method for the construction of carbon–carbon bonds [1-5]
We report the synthesis of 1-[bis(trifluoromethyl)phosphine]-1’-oxazolinylferrocene ligands and their application in Pd-catalyzed allylic alkylation reactions of monosubstituted allyl substrates with excellent regio- and enantioselectivity
As depicted in Scheme 2, ligands L1a–L1d were synthesized from known compounds 3, which were obtained from ferrocene in three steps according to the reported procedures [39-41]

Summary

Introduction

The palladium-catalyzed asymmetric allylic alkylation (AAA) reaction is becoming an efficient method for the construction of carbon–carbon bonds [1-5]. With monosubstituted allyl substrates, the palladium-catalyzed allylic substitution reaction prefers to give linear products rather than the branched ones [6-9] (Scheme 1). The regio- and enantioselective allylic substitution reaction of monosubstituted allylic substrates to preferably obtain the branched products is one of the contin-

Results

Conclusion