Trifunctionalized allenes. Part III. Electrophilic cyclization and cycloisomerization of 4-phosphorylated 5-hydroxypenta-2,3-dienoates: An expedient synthetic method to construct 2,5-dihydro-1,2-oxaphospholes, furan-2(5H)-ones and 2,5-dihydrofurans

Abstract

This chapter discusses the reactions of 4-phosphorylated 5-hydroxypenta-2,3-dienoates with protected or unprotected hydroxy group involving 5-endo-trig cyclizations. Reactions with electrophiles produce mixtures of the 2,5-dihydro-1,2-oxaphosphole-5-carboxylates and the 5-phosphoryl-furan-2(5H)-ones by competitive electrophilic cyclization due to the neighboring phosphonate (phosphine oxide) and the carboxylate groups participation. 4-Phosphorylated 5-hydroxypenta-2,3-dienoates were smoothly converted into the corresponding 4-phosphoryl-2,5-dihydrofuran-2-carboxylates by using 5 mol% of a silver salt as a catalyst in the 5-endo-trig cycloisomerization reaction.

Graphical Abstract

Keywords:

• 4-Phosphorylated 5-hydroxypenta-2,3-dienoates
• electrophilic cyclization
• 2,5-dihydro-1,2-oxaphospholes
• furan-2(5H)-ones
• silver-catalyzed cycloisomerization
• 2,5-dihydrofurans

Acknowledgment

Dedicated to Professor Dr Toru Minami from Kyushu Institute of Technology, Tobata, Kitakyushu, Japan on the occasion of his 80th anniversary.

Disclosure statement

The authors declare no conflict of interest.

Additional information

Funding

Financial support by the Research Fund of the Konstantin Preslavsky University of Shumen under Projects Nos. RD-08-158/2018 and RD-08-94/2019 is gratefully acknowledged.