Metal-Free, Regio- and Stereoselective Synthesis of Linear (E)-Allylic

May 12, 2015 - A variety of allylic acetates and derivatives were synthesized by an efficient two-step protocol that employs readily available termina...
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Letter pubs.acs.org/OrgLett

Metal-Free, Regio- and Stereoselective Synthesis of Linear (E)‑Allylic Compounds Using C, N, O, and S Nucleophiles Xiaojun Huang, Brandon Fulton, Kana White, and Alejandro Bugarin* Department of Chemistry and Biochemistry, University of Texas at Arlington, Arlington, Texas 76019, United States S Supporting Information *

ABSTRACT: A variety of allylic acetates and derivatives were synthesized by an efficient two-step protocol that employs readily available terminal alkenes as starting materials. This method is highly regio- and stereoselective, affording the linear (E)- isomer as the sole adduct. This process tolerates several functional groups including halogen-containing molecules, and it is general for weak oxygen, carbon, nitrogen, and sulfur nucleophiles. Furthermore, adducts were obtained in good to excellent yields.

A

Table 1. Optimization of Reaction Conditionsa

llylic acetates and related functional groups are abundant in natural products as well as organic materials. Moreover,

AcOR (mol %)

base (2 equiv)

solvent

yieldb (%)

c

Pd(OAc)2 (50) Pd(OAc)2 (50) AcOH (110) AcOH (110) AcOH (110) AcOH (110) AcOH (110) AcOH (110) AcOH (110) AcOH (110) AcOH (110) AcOH (110) AcOH (110) AcOH (110) AcOH (110) AcOH (110) AcOH (0)

none K2CO3 none K2CO3 K2CO3 K2CO3 K2CO3 K2CO3 Cs2CO3 DBU Na2CO3 DMAP Et3N i-Pr2EtN KOtBu KOH DBU

DMSO DMSO DMSO DMSO DMA DMF toluene THF DMSO DMSO DMSO DMSO DMSO DMSO DMSO DMSO DMSO

24 83 0 84 60 50