Preliminary results of an examination of factors influencing the stoichiometry and regioselectivity of the Paterno-Buchi reaction between aliphatic aldehydes and nonsymmetrical allenes are divulged. Surprisingly little regioselectivity was seen with 3-methyl-1,2-butadiene (6); however, 1-ethoxy-1,2-propadiene (14) provided a single regioisomer. Copyright (C) 1996 Elsevier Science Ltd