A novel transformation of α-substituted benzylcyanides by hydroxylation of benzyl sites using cultured cells of cotton, Gossypium hirsutum, producing alkano- or benzophenones via presumably α-cyanohydrin is demonstrated. Also regioselective hydroxylation of 4S-(−)-perillyl alcohol and 3S-(−)-citronellol by cultured suspension cells of Catharanthus roseus is reported.
证明了使用棉花的棉花细胞培养的细胞通过苄基位的羟基化对α-取代的苄基氰的新型转化,其推测通过α-氰醇产生链烷酮或二苯甲酮。还报道了由长春花培养的悬浮细胞对4 S -(-)-紫苏醇和3 S -(-)-香茅醇的区域选择性羟基化。
Rhodium-Catalyzed Ring Opening of Benzocyclobutenols with Site-Selectivity Complementary to Thermal Ring Opening
A rhodium catalyst induced ring opening of benzocyclobutenols with selective cleavage of the C(sp(2))-C(sp(3)) bond adjacent to the hydroxyl group. The site-selectivity markedly contrasted with that of their thermal ring-opening reaction. The rhodium-catalyzed ring opening led to the development of a new alkyne insertion reaction constructing a dihydronaphthalene framework.
Regioselectivity of the Base-Induced Ring Cleavage of 1-Oxygenated Derivatives of Cyclobutabenzene
作者:Abha Gokhale、Peter Schiess
DOI:10.1002/hlca.19980810207
日期:1998.2.4
products through distal and/or proximal cleavage of the strained four-memberedring via benzyl carbanion 4 and/or aryl carbanion 5. A systematic study of this process reveals the relative stability of the two isomeric carbanions 4 and 5 as a key factor in determining the course of the ring-cleavage reaction. While benzyl carbanions 4 can be trapped with carbon electrophiles, attempts at trapping aryl
The development of innovative strategies for the synthesis of N-heterocyclic compounds is an important topic in organic synthesis. Ring expansion methods to form large N-heterocycles often involve the cycloaddition of strained aza rings with π bonds. However, in some cases such strategies suffer from some limitations owing to the difficulties in controlling the regioselectivity and the accessibility
Thermal addition reactions to benzocyclobutenones studied by flash photolysis
作者:P. Schiess、M. Eberle、M. Huys-Francotte、J. Wirz
DOI:10.1016/s0040-4039(01)80210-0
日期:1984.1
Ortho-quinoid vinylketenes 2 have been generated through flashphotolysis of benzocyclobutenones 1. A kinetic study of intermolecular addition reactions of 2 competing with the recyclization 2 → 1 reveals strikingly different substituent effects for the addition of methanol and of dienophiles.