Preparation of tri- and tetrasubstituted allenes via regioselective lateral metalation of benzylic (trimethylsilyl)alkynes using TMPZnCl·LiCl

Pauline Quinio; Cyril François; Ana Escribano Cuesta; Andreas K Steib; Florian Achrainer; Hendrik Zipse; Konstantin Karaghiosoff; Paul Knochel

doi:10.1021/acs.orglett.5b00114

Preparation of tri- and tetrasubstituted allenes via regioselective lateral metalation of benzylic (trimethylsilyl)alkynes using TMPZnCl·LiCl

Org Lett. 2015 Feb 20;17(4):1010-3. doi: 10.1021/acs.orglett.5b00114. Epub 2015 Feb 9.

Authors

Pauline Quinio¹, Cyril François, Ana Escribano Cuesta, Andreas K Steib, Florian Achrainer, Hendrik Zipse, Konstantin Karaghiosoff, Paul Knochel

Affiliation

¹ Department Chemie, Ludwig-Maximilians-Universität , Butenandtstrasse 5-13, 81377 München, Germany.

PMID: 25662448
DOI: 10.1021/acs.orglett.5b00114

Abstract

The zincation of various 1-(trimethylsilyl)-3-aryl-1-propynes with TMPZnCl·LiCl followed by a Pd-catalyzed coupling with aryl halides provides arylated allenes in 52-92% yield. Subsequent metalation with TMPZnCl·LiCl and cross-coupling with a second different aryl halide provides regioselectively tetrasubstituted allenes in 42-70% yield. This sequence can be performed in a one-pot procedure. DFT calculations and NMR studies support the formation of allenylzinc and propargyllithium intermediates starting from 1-(trimethylsilyl)-3-phenyl-1-propyne.

Publication types

Research Support, Non-U.S. Gov't