“…Finally, the ease of ring opening of the intermediate spirohexadienyl radical should reflect the stability of the product. Other examples of Ar 2 -5 cycliza tion include the formation of indanones (74,88), e.g., 157 -> 158 -> 159 (88), and ring closure of PhOCOCH 2 ' (351), 2-arylbenzoyl radicals (352), PhCH=CHÒH 2 (353), and PhC(CH 2 CH 2 )CH 2 CH 2 (119). Numerous examples of ring closure in arylalkyl and similar radicals have been summarized in previous reviews (4, 6-6b).…”