Synthesis of diisopropylcyclopropenone and X-ray structure of its dichlorodimethyltin(IV) adduct

Results and Discussion Dehydrobromination of 3,5-dibromo-2,6-dimethylheptan-4-one was carried out using sodium hydride in tetrahydrofuran followed by addition of aqueous hydrochloric acid. Typical procedures for the isolation of cyclopropenones involve an extraction of the organics using diethyl ether or petroleum ether. We found that this procedure, however, gave none of the desired product. Collection of the aqueous layer followed by extraction with a more polar organic solvent, such as dichloromethane, did, however, give us our desired cyclopropenone. Apparently, 1 is more soluble in water than in diethyl ether or petroleum ether. O(i) NaHSnMe2Cl2BrBrOOSnMeClMeClSnMeClMeClO(ii) HCl(aq) 12 Scheme 1 Figure 1. ORTEP of the asymmetric unit of compound 2 (30% probability ellipsoids). Selected bond distances (Å) and angles (°): C(1)–O(1) 1.229(6), C(1)–C(2) 1.379(7), C(2)–C(3) 1.334(8), C(1)–C(3) 1.388(8), C(3)–C(4) 1.491(8), C(2)–C(7) 1.499(6), Sn–O(1) 2.366(4), Sn–Cl(1) 2.4822(16), Sn–Cl(2) 2.3765(14), Sn–C(10) 2.092(6), Sn–C(11) 2.091(5), Sn–Cl(1’) 3.5040(16), Sn–O(1)–C(1) 130.5(3), Cl(1)–Sn–Cl(1’) 81.82(5), Sn–Cl(1)–Sn’ 98.18(5).