2-Biphenylsulfonyl diazomethane, photolysis

Intramolecular attack of the carbenes shown in Scheme 30a provides benzo[6]cyclo-hepta[(5 ]-furans and -thiophenes, but the nitrogen analogue (X = NH) yields 9,10-dihydro-acridine 81AJC1037). Photolysis of 2-biphenyl isocyanide (Scheme 30b) (72JOC3571) and thermolysis of 2-biphenylsulfonyl diazomethane (Scheme 30c) (72CC893) also result in ring expansion. 

Intramolecular attack of the carbenes 32 provides benzo[7]cyclohepta[<7] furans and thiophenes 33 (Scheme 15). Photolysis of 2-biphenyl isocyanide 34 (Scheme 16) <1972JOC3571> and thermolysis of 2-biphenylsulfonyl diazomethane 35 (Scheme 17) <1972CC893> also result in the formation of ring expanded products. 

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See also in sourсe #XX -- [ ]

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