Ethoxy-3-phenyl-2-propyne

An alternative interpretation to the mechanism proposed in Scheme 7.7, could be the protonation of allenyl intermediate 13 before the addition of a new hydride, to form free allene 15. The subsequent reduction of this compound would also lead to allyl ethers 3 in a pathway fully compatible with the observed deuteration pattern. To exclude this possibility, the authors of the original work prepared allene 15 from 1-ethoxy-3-phenyl-2-propyne and BuLi, (formulate the reaction ) and treated it with NaBH4 in EtOH under the same conditions employed for compound 9. The allene 15 was recovered unchanged after several hours of reaction (Scheme 7.8). 

Reactions. - Photoreactions. 3-Phenyl-1,2-benzisothiazoles (21 X=H, Cl) and electron-rich alkynes (ethoxyacetylene, ethoxy-propyne, and diethylaminopropyne) undergo photocycloaddition to give substituted 3>4-benzo-2,6-thiazabieyclo[3 2.0Jhepta-3,6-dienes (22 R=H,CHj,R =0Et R=NEt2,R =CH, respectively), and smaller amounts of other products. 1,4-Benzothiazepine... 

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