Tandem ring-opening and formal [3+2] cycloaddition of furo[2,3-d]pyrimidine-2,4-diones

The base promoted tandem annulation reaction of activated cyclic 1,3-dipolarophiles such as 2-arylidene-1,3-indanediones, 2-(o-hydroxybenzylidene)-1,3-indanediones and 3-methyleneoxindoles with functionalized furo[2,3-d]pyrimidine-2,4-diones was systematically investigated. This reaction provided efficient synthetic protocols for complex dispiro/dispiro fused tricyclic compounds including dispiro[indene-2,3 & PRIME;-cyclopentane-1 & PRIME;,5 & PRIME;& PRIME;-pyrimidines], dispiro[indoline-3,3 & PRIME;-cyclopentane-1 & PRIME;,5 & PRIME;& PRIME;-pyrimidines] and spiro[cyclopenta[c]indeno[1,2-b]chromene-3,5 & PRIME;-pyrimidines] in good yields and with high diastereoselectivity. The reaction was believed to proceed via sequential ring-opening of the furyl ring, formal [3 + 2] cycloaddition and annulation of the o-hydroxyphenyl group.

Automated summary

The base promoted tandem annulation reaction of activated cyclic 1,3-dipolarophiles with functionalized furo[2,3-d]pyrimidine-2,4-diones provided efficient synthetic protocols for complex dispiro/dispiro fused tricyclic compounds. This reaction proceeded via sequential ring-opening, formal [3 + 2] cycloaddition, and annulation processes.