Heterocyclic Compounds in Alkaloid Synthesis

Snieckus, Victor

doi:10.1016/b978-0-12-610509-4.50009-9

Cited by 4 publications

(1 citation statement)

References 269 publications

(63 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Far-Ultraviolet spectra, 170 Fischer Tropsch synthesis, 124 Flash vapor pyrolysis, 178 Flavonoids, 159 Friedel-Crafts reactions, antimony pentahalides, 99 Gas phase, nucleophiles in, 11 photochemistry in, 26 Glutamyl derivatives, 78 Glycosides, 177 Halides, hydrogenolysis of, 100 Halogenation, cycloalkanes, 118 Heterocycles, see also individual rings Heterocyclic compounds, 127-144 cycloaddition reactions, 139, 140 electrophilic substitution, 134 in alkaloid synthesis, 161 new types, 62 synthesis via phosphoranes, 149, 150 three-membered, 37 Hydrazones, aryl, 104 Hydroformylation, 121 rhodium catalyst, 35 Hydrogenolysis of halides, 100 Hydroxylamine-O-sulfonic acid, 30 Hydroxylation, cis, with OsO*, 43 Iminium compounds, 5…”

mentioning

confidence: 99%

Recent Reviews. 6

1980

J. Org. Chem.

View full text Add to dashboard Cite

Most researchers in the field of second-language (L2) learning agree that adult learners draw on both implicit and explicit knowledge when engaging in the task of acquiring a new language; analogous to this view, most researchers likewise agree that L2 proficiency is achieved through a combination of 'implicit' and 'explicit' learning processes. 1 Explicit knowledge is knowledge that can be brought into awareness and can be verbalised, whilst implicit knowledge is knowledge that cannot be brought into awareness or articulated. 2 Put differently, explicit knowledge can be understood as potentially conscious knowledge, whilst implicit knowledge cannot reach consciousness. Correspondingly, explicit learning refers to situations 'when the learner has online awareness, formulating and testing conscious hypotheses in the course of learning'. Conversely, implicit learning 'describes when learning takes place without these processes; it is an unconscious process of induction resulting in intuitive knowledge that exceeds what can be expressed by learners'. 3 In other words, explicit learning occurs when a learner consciously and deliberately attempts to master language material or solve a language-related problem 4 ; implicit learning, on the other hand, is learning without conscious awareness. 5 It is generally assumed that child learners, i.e. learners who have not yet reached cognitive maturity, learn primarily implicitly. Research with children learning L2s in naturalistic settings (that is: in situations where they are totally immersed in the language) suggests that children learn very successfully-provided that the environment offers large amounts of high-quality language input over a prolonged period of time. Although children initially learn more slowly than adults, they are likely to eventually reach higher levels of proficiency than older learners-again, provided that intensive exposure to the L2 continues over a considerable number of years. 6 In classroom settings, however, children do not do nearly as well. Research with young classroom learners which compared the attainment of proficiency among children of different starting ages has shown that later starters consistently outperform younger starters on measures of L2 achievement 7 , although there are indications that children who start learning an L2 early tend to have more positive attitudes towards language and language learning than children who start later. 8 Why should older children, adolescents, and adults do better than younger children when learning a language in the classroom, i.e. in an environment that offers limited exposure to the L2 for a limited period of time? The most likely explanation for this phenomenon is the more advanced cognitive development of older children and adolescents, and the full cognitive maturity of adults. Cognitive maturity facilitates L2 learning in the typical language 1 e.g.

show abstract