organic memlcrl Rerear& section, Iaderle Laboratorfcr a Divlrion of American Cymmld Ccqany, Pearl River, I. I. (lteo.i~~I 31 JanUr.v 1966) Recently a number of addition reactlonr or @otochemlcally exoited moleculee to sxtq~~@eculas bon& hrve been dercribed (1). We would like to repox+ the renritizxM photoaddltlon reaction of -tit0 both activated andunactivated, exbrawlecular double bonde (2). 'Ihc reactions of coumarin with tetramdhybhylene, cyclopentene andketene diethylacetal are dISCUSBed. A solution of coumwin (.02l me), tetremethylethylene (.2Xl mole), benwphenone (.Od+ mDle) and dioxane (.083 iwle) wae Irradiated tbrougb pyrex glass with a 500-w&t mercury arc lamp. A 51per'centyleld of the :ounwin-tetramcthylethylene 1:l adduct I, m.p. 8l", wae obtained by this procedure. The inirared spectrum of the adduct shows strong carbonyl rbeorption at 5.7311. The n.m.r. spectrum; in accord w-BJ~the desired adduct, lhowe four methyl groups at 8.73, 8.78, 8.98 and 9.25 7(singletr), four' uwaatic hydrogen8 at 2.9 T(nnzltiplet) end two cyclobutane hydrogens, in an B pattern, at 6.62 and 6.82 r(JAP -lb c.p.8.).
*AU n.m.r. spectra were taken by w. W. F'ulwr and group on a Varian A-60
Spectrophotaneter.