Abstract: This invention relates to a process for preparing thiols and polythiols by the addition of a thiolcarboxylic acid, e.g., thiolacetic acid, to ethylenically unsaturated compounds in the presence of an initiator comprising a pinacol of the general formula: ##STR1## wherein R.sub.1 and R.sub.3 are members independently selected from the group consisting of substituted and unsubstituted aromatic radicals, R.sub.2 and R.sub.4 are members independently selected from the group consisting of substituted and unsubstituted aliphatic and aromatic radicals and X and Y are members independently selected from the group consisting of hydroxyl, alkoxy and aryloxy to obtain a thiol ester which is thereafter hydrolyzed to yield the corresponding thiol.

Abstract: The invention is directed to alkali-resistant, radiation curable compositions comprisingA. a polyeneAndB. a polythiol of the formula ##STR1## WHERE R is an aliphatic hydrocarbon moiety containing 2-6 carbon atoms, R.sub.2 is an alkylene group containing 2-6 carbon atoms, R.sub.1 is hydrogen or --OH, n is 2-6, and m is 1-2.A photosensitizer is added to the composition when curing is by U. V. radiation. The cured composition is operable as an additive plating resist in the manufacture of electronic circuitry.