HOST GUEST COMPLEXATION .48. OCTOL BUILDING-BLOCKS FOR CAVITANDS AND CARCERANDS

The scope of limitations of the syntheses of octols 1 by the fourfold condensations of various aldehydes withresorcinol and 2-substituted resorcinols are reported. At most, two stereoisomers of 1 were detected, one withC4v and the other with C2u symmetry ( NMR). With aliphatic aldehydes, only 1 (C4u) product was isolatedin yields ranging from 45 to 92%. With 4-substituted benzaldehydes (R = (4-XC6H4)), the yields and isomerratios varied with the character of the X substituent. With X = CH3 and CH3CH2, the C4ajC2v ratios were >32and the yields were 73-96%. With X = H or Br, 0^/0%, values ranged from 1.0 to >30 as a function of reactiontime. With X = OCH3 or X = C6H6, the C4l)/C2„ ratio was 1.5 and the yields were 93 and 99%, respectively.When X = NC, (CHa)3C, H02C, and AcNH, the C4u/C2i. ratios (yields) were <0.03 (52%), 0.03 (28%), 0.4 (79%),and 0.5 (52%), respectively. With X = 02N, OHC, or CH3(CH2)3C=C, no cyclic tetramer was detected. Con-densation of 2-methylresorcinol with CH3CHO gave 79% of the C4a isomer, but with C6H5CHO, C4u/C2u = <0.03(78%). No cyclic tetramer was obtained with either aldehyde and 2-nitroresorcinol or 2-bromoresorcinol. Anindeterminate mixture of isomers was produced with CH3CHO and 2-carboxyresorcinol. Crystal structures oftwo octols 1 (C4„) were determined (A = H, R = CH3 and A = H, R =CH3(CH2)3) as solvates, and these octolsexhibited bowl-shaped conformations. These compounds serve as important starting materials for the synthesesof cavitands and carcerands.