Synthesis of 6-hydroxychroman-2-methanol derivatives

Abstract

A process for producing chroman, a compound of the formula, ##STR1## or an optically active compound thereof wherein R.sub.2, R.sub.3 and R.sub.4 are each a hydrogen atom or a C.sub.1 -C.sub.4 alkyl group, which comprises reacting a compound of the formula, ##STR2## or an optically active compound thereof wherein A is an aryl group and R.sub.5 is a C.sub.1 -C.sub.4 alkyl group, with a compound of the formula, ##STR3## wherein R.sub.1 is a C.sub.1 -C.sub.3 alkyl group, X is a halogen atom and R.sub.2, R.sub.3 and R.sub.4 are as defined above, to obtain a compound of the formula, ##STR4## or an optically active compound thereof wherein A, R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are as defined above, reacting the resulting compound with methylmagnesium halide and then hydrolyzing to obtain the corresponding 4-aryl substituted 2-hydroxy-2-methylbutanal, or an optically active compound thereof, reducing the resulting compound to obtain a diol, or an optically active compound thereof, and then oxidizing the resulting compound to obtain a compound of the formula, ##STR5## or an optically active compound thereof wherein R.sub.2, R.sub.3 and R.sub.4 are as defined above, followed by reduction. Chromans, the objective compounds of this invention, are an intermediate for the synthesis of tocopherols, particularly .alpha.-tocopherol.