Influence Of β-substituents In Aldol Reactions Of Boron Enolates Of β-alkoxy Methylketones

Moderate to good levels of substrate-based 1,5-syn-stereocontrol could be achieved in the boron-mediated aldol reactions of β-tert-butyl methylketones with achiral aldehydes, independent of the nature of the β-alkoxy protecting group (P = PMB or TBS). The analysis of the relative energies of the transition structures by theoretical calculations using the density functional B3LYP shows relative energies favoring the corresponding OUT-1,5-SYN transition structures, explaining the observed 1,5-syn stereoinduction. © 2010 American Chemical Society.122150565059Blanchette, M.A., Malamas, M.S., Nantz, M.H., Roberts, J.C., Somfai, P., Whritenour, D.C., Masamune, S., Tamura, T., (1989) J. Org. Chem., 54, p. 2817Paterson, I., Oballa, R.M., Norcross, R.D., (1996) Tetrahedron Lett., 37, p. 8581Paterson, I., Gibson, K.R., Oballa, R.M., (1996) Tetrahedron Lett., 37, p. 8585Paterson, I., Collet, L.A., (2001) Tetrahedron Lett., 42, p. 1187Paterson, I., Di Francesco, M.E., Kuhn, T., (2003) Org. Lett., 5, p. 599Evans, D.A., Gage, J.R., (1990) Tetrahedron Lett., 31, p. 6129Evans, D.A., Coleman, P.J., Côté, B., (1997) J. Org. Chem., 62, p. 788Evans, D.A., Côté, B., Coleman, P.J., Connell, B.T., (2003) J. Am. Chem. Soc., 125, p. 10893Evans, D.A., Connell, B.T., (2003) J. Am. Chem. Soc., 125, p. 10899Evans, D.A., Nagorny, P., McRae, K.J., Sonntag, L.-S., Reynolds, D.J., Vounatsos, F., (2007) Angew. Chem., Int. Ed., 46, p. 545Evans, D.A., Welch, D.E., Speed, A.W.H., Moniz, G.A., Reichelt, A., Ho, S., (2009) J. Am. Chem. Soc., 131, p. 3840Denmark, S.E., Fujimori, S., Pham, S.M., (2005) J. Org. Chem., 70, p. 10823Denmark, S.E., Fujimori, S., (2001) Synlett, p. 1024Denmark, S.E., Fujimori, S., (2005) J. Am. Chem. Soc., 127, p. 8971Dias, L.C., Sousa, M.A., Zukerman-Schpector, J., Bau, R.Z., (2002) Org. Lett., 4, p. 4325Dias, L.C., Aguilar, A.M., (2006) Org. Lett., 8, p. 4629Dias, L.C., Marchi, A.A., Ferreira, M.A.B., Aguilar, A.M., (2007) Org. Lett., 9, p. 4869Dias, L.C., Marchi, A.A., Ferreira, M.A.B., Aguilar, A.M., (2008) J. Org. Chem., 73, p. 6299Dias, L.C., Pinheiro, S.M., Oliveira, V.M., Ferreira, M.A.B., Tormena, C.F., Aguilar, A.M., Zukerman-Schpector, J., Tiekink, E.R., (2009) Tetrahedron, 65, p. 8714Dias, L.C., Aguilar, A.M., (2008) Chem. Soc. Rev., 37, p. 451Dias, L.C., Aguilar, A.M., (2007) Quim. Nova, 30, p. 2007Arefolov, A., Panek, J.S., (2002) Org. Lett., 4, p. 2397Park, P.K., O'Malley, S.J., Schmidt, D.R., Leighton, J.L., (2006) J. Am. Chem. Soc., 128, p. 2796Li, P., Li, J., Arikan, F., Ahlbrecht, W., Dieckmann, M., Menche, D., (2009) J. Am. Chem. Soc., 131, p. 11678Li, P., Li, J., Arikan, F., Ahlbrecht, W., Dieckmann, M., Menche, D., (2010) J. Org. Chem., 75, p. 2429Yamaoka, Y., Yamamoto, H., (2010) J. Am. Chem. Soc., 132, p. 5354List, B., (2002) Tetrahedron, 58, p. 5573List, B., Pojarliev, P., Castello, C., (2001) Org. Lett., 3, p. 573List, B., Lerner, R.A., Barbas III, C.F., (2000) J. Am. Chem. Soc., 122, p. 2395. , See Supporting Information file for more detailsDoi, T., Numajiri, Y., Munakata, A., Takahashi, T., (2006) Org. Lett., 8, p. 531Zou, B., Wei, J., Cai, G., Ma, D., (2003) Org. Lett., 5, p. 3503Newton, R.F., Reynolds, D.P., Finch, M.A.W., Kelly, D.R., Roberts, S.M., (1979) Tetrahedron Lett., 41, p. 3981Burk, R.M., Gac, T.S., Roof, M.B., (1994) Tetrahedron Lett., 35, p. 8111Lundquist, J.T.I.V., Satterfield, A.D., Pelletier, J.C., (2006) Org. Lett., 8, p. 3915Paton, R.S., Goodman, J.M., (2006) Org. Lett., 8, p. 4299Goodman, J.M., Paton, R.S., (2007) Chem. Commun., p. 2124Paton, R.S., Goodman, J.M., (2008) J. Org. Chem., 73, p. 1253The theoretical calculations were performed with the corresponding S enantiomer of the β-alkoxy methylketone. For similar theoretical calculations performed in our group, see ref 5