With the rapid development and complex challenges of chemical substances, new drug synthesis pathways are usually the most effective.36838-71-8,4-Methylenetetrahydro-2H-pyran,as a common compound, the synthetic route is as follows.
36838-71-8, General procedure: In a dry two-neck round-bottom flask equipped with a condenser and a magnetic stirrer were successively added oxime1b(2 mmol), iodoester8(1 mmol) and the alkene3(5 mmol) in 1,2-dichloroethane (2 mL). The reaction mass was degassed with argon gas for about 30 min. (Bu3Sn)2(1.5 mmol) was then introduced and the flask was heated to 60C. The radical initiator DTBHN (t-BuON=NOt-Bu) was then added two times in portions of 0.1 mmol each at an interval of 2 h. After total consumption of the starting material, the resulting mixture was cooled to room temperature and trifluoroacetic acid was added (such as TFA/DCE = 1:4 %vol.). The reaction was monitored by TLC and after completion of the hydrolysis, the reaction mixture was concentrated under vacuum for at least 4 h to yield a dark-brown oil. This mixture was purified through a short path of deactivated silica gel doped with KF (5% -wt) with petroleum ether-EtOAc (90:10 to 80:20) and the resulting oil was subjected to further reaction. To a solution of the preceding aldehyde (1 eq) and allyltrimethylsilane3f(2 eq) in dry dichloromethane (1 M) at 0C was added dropwise TiCl4(1M solution in CH2Cl2, 1.2 eq) The colorless solution became gradually red. The ice bath was removed and the course of the reaction was monitored by T.L.C. After all the aldehyde has been consumed, water (10 mL) was added to the reaction mixture and the resulting yellow heterogeneous mixture was extracted with dichloromethane (3×10 mL). The combined organic layers were dried over anhydrous MgSO4, filtered, and concentrated in vacuo to afford a yellow oil. Purification over silica gel (Petroleum ether/EtOAc) furnished the desired lactones24.
36838-71-8 4-Methylenetetrahydro-2H-pyran 548975, aTetrahydropyrans compound, is more and more widely used in various fields.
Reference£º
Article; Landais, Yannick; Robert, Frederic; Godineau, Edouard; Huet, Laurent; Likhite, Nachiket; Tetrahedron; vol. 69; 47; (2013); p. 10073 – 10080;,
Tetrahydropyran – Wikipedia
Tetrahydropyran – an overview | ScienceDirect Topics