Simplified Olefin Isomerization by Cobalt/Silane

Introduction

Recently, the Shenvi lab has repurposed Jacobsen’s cobalt chloride complex, Co(salen,t-Bu, t-Bu)Cl, to enable positional isomerization of terminal alkenes using reversible hydrogen atom transfer (HAT). This cobalt pre-catalyst, when combined with a catalytic amount of organosilane, enables high-yielding isomerizations and cycloisomerizations of alkenes in the presence of strongly Lewis basic functional groups like tertiary amines and imidazoles. The Shenvi group of The Scripps Research Institute and Chemistry now offer the inexpensive, bench-top stable Co(salen,t-Bu, t-Bu)Cl complex (804010) that can be readily used outside the glovebox.

Co(salen,t-Bu, t-Bu)Cl complex (804010)

Application Scope

Table 1. Terminal Alkene Isomerization

Substrate	Product	Yield	E/Z
		83%	3:1
		69%	10:1
		92%	3:1

Advantages

• Functional group tolerance
• Diastereoselective isomerization
• Prevents reduction
• No need for a glove box
• High-yielding, high-profiting and low-cost reactions (Scheme 2)

Representative Schemes

References

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