Synlett 2003(1): 0127-0137
DOI: 10.1055/s-2003-36234
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© Georg Thieme Verlag Stuttgart · New York

Strategies for the Preparation of Differentially Protected ortho-Prenylated Phenols

Christophe Hoarau, Thomas R. R. Pettus*a
Department of Chemistry and Biochemistry, University of California at Santa Barbara, Santa Barbara, California 93106, USA
Fax: +1(805)8935690; e-Mail: pettus@chem.ucsb.edu;
Further Information

Publication History

Received 22 July 2002
Publication Date:
18 December 2002 (online)

Abstract

A new process for ortho-prenylation of phenols is presented within the context of known methods. All of the processes are briefly assessed with regards to the substitution patterns and accompanying functional groups tolerated by each strategy. The conclusion reached is that a new procedure using ortho-quinone methides, for which an experimental protocol is provided, offers the greatest generality and flexibility in the preparation of ortho-prenylated phenol derivatives.

  • 1 Introduction

  • 2 Desymmetrization of Dihydroxy Aromatics

  • 3 Directed ortho-Metalation (DoM) and Alkylation

  • 4 Metal-Halogen Exchange and Metal-Mediated Coupling

  • 5 Phenoxide ortho-C-Alkylation

  • 6 Claisen Rearrangement

  • 7 Friedel-Crafts-like Prenylations

  • 8 Birch Reduction of 2,2-Dimethyl-2H-chromenes

  • 9 Net Conjugate Addition to para-Quinone

  • 10 Benzylic Couplings

  • 11 Conclusions

32

The lability of the remaining OBOC residue in 92 and our inability to purify this substance is believed to be responsible for the reduced yield of 97 when compared with the overall yields of 95, 96 and 98.