COA of Formula: C15H16O2《A ketal-tethered RCM strategy toward the synthesis of spiroketal related natural products》 was published in 2006. The authors were Ghosh, Sunil K.;Ko, Changhong;Liu, Jia;Wang, Jiashi;Hsung, Richard P., and the article was included in《Tetrahedron》. The author mentioned the following in the article:
An unconventional approach to construct spiroketals and spiroaminals via ring-closing metathesis [RCM] of cyclic ketals and aminals, resp., was described here. This method possesses a good generality with no loss of stereochem. integrity at the spirocenter under the standard RCM conditions. This approach was applied to the synthesis of an insect pheromone I to demonstrate its synthetic potential, and also to the synthesis of the protected C11-epi-C22-C23 fragment II (R = CH2C6H4-4-OMe, R1 = SiPh2CMe3) of spirastrellolide A. Both are proof-of-concept applications to feature a ketal-tethered RCM as an alternative strategy for construction of spiroketals. And Dimethoxydiphenylmethane (cas: 2235-01-0) was used in the research process.
Dimethoxydiphenylmethane is one of ethers-buliding-blocks. Ethers feature bent C–O–C linkages. In dimethyl ether, the bond angle is 111° and C–O distances are 141 pm. The barrier to rotation about the C–O bonds is low. COA of Formula: C15H16O2 The bonding of oxygen in ethers, alcohols, and water is similar. In the language of valence bond theory, the hybridization at oxygen is sp3.
Reference:
Ether – Wikipedia,
Ether | (C2H5)2O – PubChem