Tomioka, Hideo published the artcileButtressing effect in carbene chemistry. Effect of 3-alkyl groups on the reactions of 2-alkoxydiphenylcarbenes, Related Products of ethers-buliding-blocks, the publication is Journal of the Chemical Society, Perkin Transactions 1: Organic and Bio-Organic Chemistry (1972-1999) (1991), 471-7, database is CAplus.
Irradiation of 3,2-R(MeO)C6H3CPh:N2 (I; R = H) in Et2O at 10° gave 3-phenyldihydrofuran (II; R = H) and a small amount of 3,2-R(MeO)C6H3CHPhR1 [III; R1 = H, R = EtOCHMe (IV)]; IV was the major product when the irradiation was carried out in an Et2O matrix at -196°. With I (R = alkyl) the reaction patterns were dramatically changed. Only II (R = alkyl) were formed in Et2O at +10 or -196°. This was due to the buttressing effect of R, which prevents the 2-MeO group from lying in the plane of the Ph ring in the precursor mols. and assists the MeO group in rotating around the C-O bond toward the carbene center after elimination of N. The effect of buttressing on the generation of carbene in MeOH is also discussed.
Journal of the Chemical Society, Perkin Transactions 1: Organic and Bio-Organic Chemistry (1972-1999) published new progress about 2944-47-0. 2944-47-0 belongs to ethers-buliding-blocks, auxiliary class Benzene,Ether, name is 2-Isopropylanisole, and the molecular formula is C8H7ClO3, Related Products of ethers-buliding-blocks.
Referemce:
https://en.wikipedia.org/wiki/Ether,
Ether | (C2H5)2O – PubChem