in dichloromethane N-acetoxyaminoquinazolone (prepd. in situ from aminoquinazolinone and acid-free Pb(OAc)4 at -25°C) in CH2Cl2 is stirred for 30 min at -25°C; addn. of alkenylstannane, warming to ambient temp.; Pb(OAc)2 is filtered off, washed with NaHCO3 soln. and H2O, dried, evapd., chromy. (silica, ethyl acatate-light petroleum) yields Sn-compd. Further elution yield bezoxazin, elem. anal.;

1: 1-methyl-pyrrolidin-2-one; copper(l) iodide; dichloro bis(acetonitrile) palladium(II); triphenyl-arsane / 72 h / 80 °C / Inert atmosphere 2: carbon monoxide; palladium diacetate; 1,8-diazabicyclo[5.4.0]undec-7-ene; triphenylphosphine / N,N-dimethyl-formamide / 72 h / 120 °C / 4560.31 Torr / Autoclave View Scheme

1: 1-methyl-pyrrolidin-2-one; copper(l) iodide; dichloro bis(acetonitrile) palladium(II); triphenyl-arsane / 72 h / 80 °C / Inert atmosphere 2: carbon monoxide; palladium diacetate; triphenylphosphine / N,N-dimethyl-formamide / 72 h / 120 °C / 4560.31 Torr / Autoclave View Scheme