Benzannulated enediynyl alcohols

The conversion of the (Z)-phenylhydrazone of 5-amino-3-benzoyl-l,2,4-oxadiazole into the relevant 1,2,3-triazole in the presence of several haloacetic acids and the kinetics of the rearrangement of (Z)-arylhydrazones of 5-amino-3-benzoyl-l,2,4-oxadiazole to (2-aryl-5-phenyl-2//-l,2,3-triazol-4-yl)ureas have been reported. Treatment of benzannulated enediynyl alcohols with trifluoroacetic acid promoted a cascade sequence of cyclization reactions leading to 1,4-naphthoquinone methides (Scheme 37)7 ... 

Wang, Y.-H., Akhmedov, N.G., Petersen, J.L. and Wang, K.K. (2007) Gonstruc-tion of unusual and congested polycyclic structures via benzannulated enediynyl alcohols derived from truxenone. Journal of Organic Chemistry, 72(25), 9604— 9608. 

Scheme 3.45 Synthesis of diindeno-fused 4H-cyclopenta[t/e/]-phenanthren-4-ones via benzannulated enediynyl propargylic alcohols.

Han, X.Q., Zhang, Y.Z. and Wang, K.K. (2005) Synthesis of diindeno-fused 4H-cyclopenta[ fe/]phenanthren-4-ones and related compounds via benzannulated enediynyl propargylic alcohols. Journal of Organic Chemistry, 70(6), 2406-2408. 

The enyne-allenylphosphine oxides 120 and the benzannulated and naphthannu-lated analogs 121 and 122 having the diphenylphosphinyl group at the allenic terminus were readily prepared from the corresponding enediynyl propargylic alcohols 117,118 and 119 (Scheme 20.25) [64]. Without the unfavorable steric interactions, these conjugated derivatives smoothly underwent the Myers-Saito cyclization reaction. 

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