In Quest of “Stereoselective Switch” for On-Water Hydrothiolation of Terminal Alkynes Using Different Additives and Green Synthesis of Vicinal Dithioethers

Table 1

Role of additives in the addition of PhSH to phenylacetylene under on-water conditions at room temperature producing selectively anti-Markovnikov adducts^a.

Entry	Additive [A]^b	(E/Z) ratio^c, d	Entry	Additive [A]^b	(E/Z) ratio^c,  d
1	Nil (neat)	83 : 17	13	CuI-Catechol violet	60 : 40
2	Nil (water)	80 : 20	14	Amberlite resins (Cl)	58 : 42
3	NaCl	87 : 13	15	n-Bu4NBr	57 : 43
4	Sucrose	85 : 15	16	D-Glucose	56 : 44
5	CF3COOH	78 : 22	17	CuI	52 : 48
6	BF3·Et2O	76 : 24	18	Cholesterol	51 : 49
7	Catechol violet	75 : 25	19	CTAB	49 : 51
8	L-Proline	70 : 30	20	FeCl3·6H2O	44 : 56
9	Glycin	69 : 31	21	Amberlyst resins (OH)	40 : 60
10	Starch	64 : 36	22	D-Glucose and FeCl3·6H2O	35 : 65
11^e	Water (65°C)	88 : 12	23	Amberlite resins (Cl) and FeCl3·6H2O	22 : 78
12	Water (65°C)	64 : 36

aReaction conditions: phenyl acetylene (0.5 mmol), PhSH (0.55 mmol), water (1 mL), 2 h. bAdditive [A] (2 mol %). cE/Z ratio was determined by ¹H NMR of the crude mixture. dYield of the mixture of stereoisomers after chromatographic purification varies in the range 80–90%. eThe reaction was continued for 10 h; all other reactions were carried out at room temperature unless otherwise mentioned.