A general synthetic route to 6,6-substituted-6H-dibenzo[b,d]pyrans from dibenzofuran.

Abstract

The reaction of dibenzofuran 1, lithium pieces (2.2 equiv), and TMEDA (2.2 equiv) in dry ether under reflux led to a solution of the corresponding C,O-dilithiated intermediate 2 which, upon treatment with different ketones or aldehydes (0.8 equiv) at -78 degrees C, afforded, after hydrolysis and dehydration, 6,6-substituted-6H-dibenzo[b,d]pyrans 3 in good yields. The reaction undergoes reductive ring opening and cyclization, and the intermediate diol 4e was isolated.

• Authors: Bin Wang, Minxiong Li, Shansheng Xu, Haibin Song, Baiquan Wang
• Journal: The Journal of organic chemistry (J Org Chem) Vol. 71 Issue 21 Pg. 8291-3 (Oct 13 2006) ISSN: 0022-3263 [Print] United States
• PMID: 17025329 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Benzofurans
• Organometallic Compounds
• Pyrans
• phenyllithium
• dibenzofuran
• Lithium

Topics

• Benzofurans (chemistry)
• Lithium
• Organometallic Compounds
• Pyrans (chemical synthesis)