Carbolithiation of Simple Terminal and Strained Internal Alkenes by the Naphthalene and the Biphenyl Dianion: New Modes of Reactivity of Highly Reduced Organic Species in Solution

Mechanistic and Synthetic Studies of Biaryl Birch Reductions

The Birch reduction of biaryls generally converts one of the two arenes into a cyclohexa-1,4-diene. Biaryls are more reactive than monocyclic arenes under the Birch conditions. Unlike the reduction of monocyclic arenes, biaryl reduction proceeds through two consecutive electron transfer steps before the protonation of the dianion intermediate. The biaryl reductions and subsequent alkylations in one pot rapidly increase the molecular complexity and thus have been used in the synthesis of natural products and drug-like molecules.

1 Introduction

2 The Physical Organic Chemistry of the Birch Reduction of Biaryls

3 Biaryls as the Mediators of Electron Transfer

4 Methods for the Dissolving-Metal Reduction of Biaryls

5 Intercepting the Biaryl Reduction Intermediates with Electrophiles

6 Synthetic Applications of the Dissolving-Metal-Mediated Reductions of Biaryls

7 Outlook

Spontaneous disproportionation of lithium biphenyl in solution: a combined experimental and theoretical study

Spontaneous disproportionation of lithium biphenyl radical anion into a lithium biphenyl dianion plus neutral biphenyl, according to 2LiBiph ⇄ Li₂Biph + Biph, has been evidenced experimentally by UV-vis spectroscopy and backed up theoretically using TDDFT methods.

Consecutive cyclization of allylaminoalkene by intramolecular aminolithiation-carbolithiation

Consecutive cyclization of allylaminoalkenes by tandem aminolithiation-carbolithiation proceeded smoothly by using a lithium amide as a lithiating agent as well as protonating agent to give bicyclic amines, octahydroindolizine and hexahydro-1 H-pyrrolizine, in reasonably high yield and diastereoselectivity.